Imágenes de páginas
PDF
EPUB

legs. It appears that when very young the crab holds over its back a minute bit of shell or gravel upon which the Anemone lodges, and afterwards, by expanding its basal pellicle as the crab grows, provides it with a permanent protection. This Anemone was never found except upon the crab's back, and the crab was not found without it. A very different crab found at Panama, Hepatella amica Smith, * carries upon its back Sagartia carcinophila Verrill, but in this case the connection is probably less intimate, and not so permanent.

THE HALIOTIS, OR PEARLY EAR-SHELL.

BY ROBERT E. C. STEARNS.

THERE is a family of Mollusca whose beautiful shells are frequently seen ornamenting thė parlor mantel or centre table, the admiration of all on account of the brilliant colors and iridescence of their pearly interiors.

These shells are popularly called Sea-ears, but the scientific name is Haliotis, from the Greek halios, marine, and otis, ear. In the different countries where these shells are found, there are local names by which they are known. In California the people call them Abalones, while they are called "Meerohren by the Germans, Telinga maloli or Bia sacatsjo by the Malays, and Hovileij by the Amboynese,” according to Adanson. "The Eolians gave it the pretty name of Venus's Ear. It is the 'Mother-of-pearl,' or 'Nor

Hepatella amica Smith, gen. et., sp. nov. The genus Hepatella differs from Hepatus in having the carapax rectangular in outline, in the much larger facial region, the very small eyes and very short eye peduncles, and in wanting wholly the depression below the orbit; the carapax is also much thicker, and the lateral regions are concave above. In this species the gastric and posterior branchial regions are protuberant and granulous, as is also the middle of the cardiac region, the rest of the carapax smooth; the lateral margins nearly parallel posteriorly but rounded anteriorly, the edge thin and armed with about twelve irregular and sharp teeth; ambulatory legs very short and crested; the sternum deeply punctate and vermiculated, and the male abdomen very narrow, acutely pointed, and five jointed. Length of carapax, 11.5 millimetres; breadth 15.8.

man-shell' of old English writers ; ' Ormier' (contracted from oreille-de-mer) of the French, 'Lapa burra' of the Portuguese, 'Orecchiale' of the Italians, and 'Patella reale of the Sicilians.” The Cherbourg fish-women call it, according to Jeffreys, " Si ieu(six yeux), from an idea that the orifices in the shells are real eyelets or peep-holes.

The shells of Haliotis are, through ignorance, frequently confounded with those of the Meleagrina margaritifera, or pearl-bearing oyster, which is the true mother-of-pearl shell, from which are obtained the beautiful pearls used in the manufacture of various articles of jewelry. The Meleagrinæ are bivalves, their shelly covering being composed of two pieces or valves, as is the case with the common oyster, scallop and clam, while the Haliotis has an univalve shell, complete in one piece or valve, without joint or hinge.

The Haliotides belong to the class Gasteropoda (gaster, belly, pous, feet), which comprises species of Mollusks that are characterized by their creeping upon, or by means of a muscular expansion of the body, called a foot. They belong to the order of Scutibranchiata (scutum, a shield, branchiæ, gills), the gills, or lung, being protected by a shield of shelly or calcareous matter. The shells of Haliotis, however, resemble, in general outline, the form of the human ear; several of the species, of which as many as eighty are known, are rough externally though brilliant within.

The shell of Haliotis (Fig. 43) may be compared to a flattened Turbo, or top-shell, with small apex whorls and a disproportionately large body or basal whorl, depressed, largely open, and having but a slightly elevated spire, composed of but few whorls. Again, as regards form, it holds the same position in comparison with Turbo that Concholepas does to Purpura, Sigaretus to Natica, and to follow the analogies into the Geophila, Vitrina to the more closely whorled trochiform land species.

[ocr errors]

Fig. 43.

[ocr errors]

The animal (Fig. 44; a, tentacle; b, eyes; c, holes in the shell for the passage of the tentacles, d and f; e, foot) adheres to the rock like the Patellas and Fissurellas. To the latter genus it is somewhat allied through its anatomy; the arrangement of the teeth upon the lingual ribbon is said to be like that of Trochus. Cuvier found that every individual he examined had an ovary, and therefore concluded

Fig. 44.

[graphic]
[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]

*

that the Haliotides were hermaphrodites.* Swainson considered them as occupying a position among the phytophagous, or vegetable eating gasteropods, analogous to the Volutidæ among the Zoophaga, or carnivorous mollusks; the analogy being particularly apparent by a comparison of Haliotis with the Melo group of the Volutes.

The chief peculiarity of these animals is, that their shells are perforated with a regular series of holes for the passage of the sea-water to the respiratory organs, analogous to the single vertical and nearly central hole in the shell of Fissurella. The holes in Haliotis are placed in a row nearly equidistant from centre to centre, upon the left side of the shell, parallel with the columellar lip, and being required only in that part of the shell which covers the branchial cavity, those nearest the apex are closed or grow up as the animal advances in growth. The holes furnish a passage for slender tentacular filaments which the animal can protrude at pleasure; the hole or notch for the passage of the anal siphon is situated at the posterior margin of the shell. The animal of Haliotis, according to P. P. Carpenter, " has two gills and two auricles, instead of one, as in the top-shells." Its head is blunt and terminates in a short muzzle, with two subulate tentacles and two stout eye peduncles at their bases. Upon the upper extremity of the foot it has a rudimentary operculigerons lobe, but no operculum. The foot is very large,

* In July, 1867, specimens of the shells of Haliotis, from Monterey, were received by me, which combined the peculiarities of the two very distinct species, H. rufescens and H. Cracherodii, to a remarkable degree. These abnormal forms are of exceed. ingly rare occurrence, and in the great number of specimens that I have examined, I have been unable to obtain additional illustrations. The specimens referred to impressed ine as being hybrids, and I feel confident that farther investigation will corroborate any opinion that species of Haliotis will occasionally cross. (Proceedings of the California Academy of Sciences, Vol. iii, p. 361.)

, rounded at the ends and fringed with thread-like tentaculæ, which, when the animal is protruded from the shell, below the surface of the water, are gently swayed with a somewhat vibratory motion. "The muscular attachment, instead of being horseshoe shaped as in ordinary univalves, is round and central, as in the oyster." (Carpenter.)

In adult shells in many of the species, the roughened portion of the interior indicates the area of the muscular attachment, while in young specimens the impression of the muscle is not shown.

The Haliotides are sedentary in their habits, as one would suppose, being both vegetarians and conservatives, and though capable of locomotion, they move but little and quite slowly; their structure, as seen in the powerful muscular foot, shows it is made for adhesion. They attach themselves to the rocks with the greatest tenacity, and I have often found it exceedingly difficult to remove them, though using a stout trowel, of a shape similar to the kind used by bricklayers.

[ocr errors]
[ocr errors]

The animal of Haliotis is exceedingly tenacious of life. I have frequently removed it from the shell by means of a sharp knife, and by throwing it, minus the shell, back into the water, it would at once descend and place itself in its normal position upon a rock, to which it would adhere with apparently as much tenacity as before it was deprived of its shelly covering.

"The brilliant and highly colored interior of these shells producing sometimes an iridescent effect, has been attributed by Sir David Brewster, Dr. Carpenter, and others, to minute striæ, or grooves, on the surface of the nacre, which alternate with others of animal membrane. The color is produced by the nature of the laminæ, which decompose the light in consequence of the interference caused by the reflection from two sides of each film, as may be seen in soapbubbles. The nacreous laminæ, when magnified, indicate a minute cellular structure. The cells are of a long oval form, and their short diameter is not above govo of an inch.” (Jeffreys.) The animal of Haliotis is mentioned by Athenæus as being exceedingly nutritious but indigestible. "The maritime negroes of Senegal esteemed one species a great delicacy:

H. tuberculata is habitually eaten by the poor in the north of France and our Channel Isles, where it is occasionally cooked and served at the tables of the rich. It requires a good deal of beating and stewing to make it tender.” (Jeffreys.)

In New Zealand the animal of H. iris is eaten by the natives, and is called "Mutton-fish.” Another species is eaten in Japan. In California the animals of the two most abundant species, H. rufescens and H. Cracherodii, are frequently eaten by the Americans residing along the coast, and are a common article of food with the Chinese, who collect them in large quantities at Monterey, and other favorable localities north and south of that place, remove the animals from the shells, and dry the former for future use or for export to their native country.

« AnteriorContinuar »