under the magnifier. Then there are certain species of shells (Chiton, Pl. 4, fig. 1) which cling to the stones, limpetlike, but instead of having a shell of one piece covering their back, the shell is composed of eight transverse pieces, one lapping over the other. When detached from the rock they often roll up like a pill-bug. On the eastern coast of Maine there is one large species which can be taken from the rocks at low-water mark. The species dredged in Massachusetts Bay are generally small; one or two of them are brightly colored with shades of red.

Two other species called Velutina (Pl. 4, figs. 4, 5) are often found adhering to the rocks brought up in this manner. By far the most beautiful and interesting animals are contained in the little cells which often cover the rocks from deep water. They are arranged in little patches like mats, some species making a perfectly circular figure, others covering the rocks in irregular patches. These belong to the lowest group of mollusks, and are called Polyzoa. Under the microscope the mass is seen composed of little cells, arranged like the stones in a pavement. Each one of these cells has a little opening protected by a small lid, which opens to allow the animal within to protrude a tuft of minute feelers. It would require too long a time to show the affinity of these animals to the clam and oyster, yet they are among the lowest forms of this group. There are many species on our coast, some of which have been described as new, others are similar to British species.

We figure on Plate 4 several species of shells one is likely to dredge on our New England coast, though representing but a small portion of the species that may be found, and we may mention here, with propriety, that the State of Massachusetts-with that liberality that has always characterized the acts of its legislature-has now in preparation a new edition of "Gould's Report on the Invertebrate animals of the State." This book, when published, will contain carefully engraved figures of all the species of shells found

within its limits, and the marine species alone (containing all the animals that belong to the branch of mollusca, though many have no hard calcareous shells) number three hundred and sixteen. Several of these are cuttle-fishes, and there are many mollusks which have no shells, the branchiæ or gills being naked; hence they are called Nudibranchia. They comprise the most beautiful animals in the branch of Mollusca, for certain species are very brilliantly colored.

The species figured on the plate are among the few that the collector is likely to bring up while dredging in our bays and inlets, in depths of from ten to fifteen fathoms. Should he be ambitious to throw his dredge into depths of fifty or one hundred fathoms, many other species will be secured that he could not get in water of less depth.

The outlines given will be found sufficiently accurate to enable the collector to identify the species represented. Fig. 1 represents Chiton albus; the shell is not quite half an inch in length; it is generally a dead white color. Figs. 4 and 5 represent Velutina haliotoides and V. zonata, the latter differing from the former in having a more solid shell, and in having the shell marked with bands of brown. Fig. 6 is the Natica immaculata, a pure white shell of the size represented; very common. Fig. 13 represents another species, Natica clausa; color from a white to a dark reddish brown. The little lid that closes the aperture of most marine shells is in this species white and shelly, and not of the horny consistency characterizing the opercula of most shells in our region. Pandora trilineata (Fig. 24) is easily distinguished by its white pearly color, and the manner in which the valves are pressed together. Lyonsia hyalina (Fig. 20) has a very fragile translucent shell covered with radiating wrinkles. Thyasira Gouldii (Fig. 18) has a delicate white shell, along one margin of which is a deep fold. The shell of Astarte castanea (Fig. 22) is quite solid, and chestnut-colored. It is found abundantly in Provincetown harbor at low water. Astarte sulcata (Fig. 25) is known by its strongly marked

concentric ridges. The color in young specimens is very light-brown; in old ones the shell is of a brownish olive color. Cardita borealis (Fig. 28) has a brownish shell with the ribs crenulated. Cardium pinnulatum (Fig. 33) has a dingy white shell, ornamented with about twenty-five ribs, each of which has a series of little scales. Yoldia limatula (Fig. 30) has a beautifully polished shell, of a light green color. The hinge is complicated by a number of long sharp teeth, so closely interlocked, that it is difficult to separate the valves without breaking them. Tellina tenera (Fig. 31) has a white iridescent shell. Nucula tenuis (Fig. 27) is smooth and green in color. Nucula delphinodonta (Fig. 29) is brownish green. All the Nuculas have the same peculiar hinge of numerous interlocking teeth. Crenella glandula (Fig. 26) has a brownish yellow shell, marked with minute. radiating lines. Terebratulina septentrionalis (Fig. 32), though apparently related to the other bivalves, is widely different from them and belongs to another order; the shell is secured to the bottom, generally on stones, by a fleshy peduncle which passes through a hole in the upper valve. Dentalium striolatum (Fig. 9) has a shell like a long curved tapering tube. Scalaria Groenlandica (Fig. 12) has a shell that looks more like a tropical species than a denizen of our cold northern waters. The shell is very attractive, with its turreted spire banded by prominent ribs. It is related to the foreign species, commonly called the "Wentle trap," which formerly brought fabulous prices among shell collectors. Margarita undulata (Fig. 16) is one of our most beautiful marine shells. The color of the shell when fresh is rose-red with a pearly lustre. Another species of this genus, Margarita cinerea (Fig. 17), is ashy white. There are several species on the coast, and all are so characteristic that they can be easily identified. Cylichna alba (Fig. 23) is bluish white. Turritella erosa (Fig. 11) has a pale brown shell, and Odostomia producta (Fig. 10) has a light browncolored shell. Bela harpularia (Fig. 7) is brownish in color,

Trito

and Bela turricula (Fig. 8) is thin and pure white. nium pygmæum (Fig. 14) is yellowish white. Admete viridula (Fig. 15) is white. Trichotropis borealis (Fig. 21) is yellowish in color. Aporrhais occidentalis (Fig. 19) is one of the most singular shells that we have. It is rare on our

coast, but is common towards Newfoundland.

We must bear in mind that the species mentioned are a few among the many that most likely will be collected in dredging on our coast.

Dredge.

EXPLANATION OF PLATE IV..

Fig. 1. Chiton albus Linn.
Figs. 2, 3. Cemoria noachina Linn.*
Fig. 4. Velutina haliotoides Müll.
Fig. 5. Velutina zonata Gould.
Fig. 6. Natica immaculata Totten.
Fig. 7. Bela harpularia Couthouy.
Fig. 8. Bela turricula Mont.
Fig. 9. Dentalium striolatum Stimpson.
Fig. 10. Odostomia producta Adams.*
Fig. 11. Turritella erosa Couth.
Fig. 12. Scalaria Grænlandica Perry.
Fig. 13. Natica clausa Sowerby.
Fig. 14. Tritonium pygmæum Gould.
Fig. 15, Admete viridula Fabr.
Fig. 16. Margarita undulata Sby.
Fig. 17. Margarita cinerea Couth.

Fig. 18. Cryptodon Gouldii Phil.*
Fig. 19. Aporrhais occidentalis Beck.
Fig. 20. Lyonsia hyalina Conrad.
Fig. 21. Trichotropis borealis Sby.
Fig. 22. Astarte castanea Say.
Fig. 23. Cylichna alba Brown.
Fig, 24. Pandora trilineata Say.
Fig. 25. Astarte sulcata Mont.
Fig. 26. Crenella glandula Tott.
Fig. 27. Nucula tenuis Mont.
Fig. 28. Cardita borealis Conrad.
Fig. 29. Nucula delphinodonta Mighels.
Fig. 30. Yoldia limatula Say.

Fig. 31. Tellina tenera Say.*

Fig. 32. Terebratulina septentrionalis Couth.
Fig. 33. Cardium pinnulatum Conrad.

*Enlarged twice.

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REVIEWS.

REVIEW OF SCANDINAVIAN NATURAL HISTORY LITERATURE IN 1867-8. By Dr. C. F. Lütken. As an appendix to my former report I beg leave to insert a review of some Norwegian papers recently received, viz., the University programme of the University of Christiania, for 1868, by Prof. Sars, and the volume, for 1867, of the Proceedings of the Society of Science of the Norwegian Metropolis, the first named of which is of unusual scientific importance and interest.

Among the many valuable works with which Prof. Sars has enriched science, his last, "Mémoires pour servir à la Connaissance des Crinoides vivants," is certainly one of the most precious, and justly so from the great interest attached to this topic, partly from the great, one might say, rather painful, minuteness and care with which the author treats every detail of form and structure in the remarkable animal described. He has been successful enough to procure, through the exertions of his son, a great number (seventy-five specimens) of the remarkable small new stalked Sea-lily, discovered by the younger Sars in the abysses of Lofoten (68° north latitude), and now described under the name of Rhizocrinus Lofotensis. Four excellently engraved plates are devoted to the illustration of the elaborate description. The memoir is written entirely in French, and it will therefore, perhaps, be thought superfluous to give an abstract of it in this place, the more as it will be easily accessible through the liberality of the University of Christiania, to all societies, etc., which are on exchanging terms with this eminent institution. But as it may perhaps be desirable that the knowledge of the discovery of so remarkable an animal should not be withheld from the readers of this journal, I shall give some notes on it, referring for a more complete account to the excellent work of the learned author itself. This crinoid has principally been taken at depths of from one hundred to three hundred fathoms on the locality stated above, where it appears to live socially. A single dead specimen was found farther to the south, in the bay of Trondjem, at a depth of eighty fathoms. Carpenter and Wyville Thomson have also found it in other parts of the North Sea, and you know that it has been recently recognized that the "Bourgueticrinus Hotesieri," from the depths of the Gulf Stream between Florida and Cuba, is in fact a Rhizocrinus, and perhaps not specifically distinct from the Norwegian one. This will, however, if the identity should be farther proved, retain its name, as the West Indian Sea-lily was, without any sufficient reasons, referred to the quite indeterminable fossil fragments described by d'Orbigny. The greatest specimen has a length of eighty millimetres, the largest part of which belongs to the stalk, which attains a length of from twelve to seventy millimetres, and consists of from twenty-two to sixty-seven