Imágenes de páginas



The genus Mesocetus was established by Van Beneden * for Mystacoceti in which the posterior part of the mandibular ramus approaches in its characters that of the Odontoceti. That is, the condyle is situated at the middle of the vertically compressed posterior border, and is more or less expanded transversely. It is thus below the superior part of the posterior extremity of the ramus, instead of constituting that part, as it does in the whalebone whales generally. That structure is naturally adapted to a more anterior direction of the glenoid cavity, as is shown by Van Beneden. The only known species of the genus is the M. agrami an Ben. from the Neocene beds of Agram in Croatia, Austria. It is of much interest that a second species is now determined to have existed in the Neocene formation of Virginia.

Van Beneden does not appear to have seen much if any of the mandibular ramus anterior to the condyle. I have a ramus nearly entire, and smaller parts of three others, and can thus locate the genus Mesocetus in relation to those already defined. In the species now to be described, the ramus has no large dental canal, but it is almost entirely filled with spongy bone of moderate coarseness. The gingival canals unite into a single tube which is not larger than one of the external gingival canals, and which runs about opposite to them or a little distance below the superior edge. In this disposition of the canals Mesocetus differs from any of the genera of Mystacoceti referred to in the preceding pages.

Char. specif.–Founded primarily on a nearly complete right mandibular ramus, and represented by the anterior part of a second ramus of a smaller individual. The distal part of the ramus of a third individual resembles the last one, but differs in some respects from it, so that the reference cannot now be made. These specimens I saw taken from the same locality and bed, and I took the type specimen myself piecemeal from the deposit. The latter is a wet phosphatic marl, and it was impos. sible to remove the specimen without damage. It has been reconstructed under my eye by my assistant so as to be in good condition.

The ramus exhibits little curvature in any direction. It is strongly compressed, and although the external face is more convex than the internal, the convexity is not great. The superior border is throughout thicker transversely than the inferior. Both are obtusely rounded anteri. orly, but both become more compressed posteriorly. The inferior border becomes rather acute posteriorly. The usual ledge is present on the internal or symphyseal side of the distal extremity. The representative of the anterior part of the dental canal issues posterior to the distal border and a little below the superior border; the external border of the

* Memoires de l'Academie royale des Sciences de Lettres et des Beaux Arts de Belgique 1982, Vol. xly.

PROC. AMER. PHILOS, soc. xxxiv. 147. T. PRINTED JUNE 12, 1895.

foramen is nutched, and a shallow groove rises from its superior angle and returns posteriorly as a shallow groove of the superior middle line. This groove disappears in a small median foramen, the first of the series of small foramina of the inner side of ihe superior border. The foramina of this series are small and represent the exits of narrow canals which run horizontally inwards so close together that a fractured surface pass. ing through them resembles a sutural surface with oblique grooves. From a median superior position they assume an internal lateral position, and disappear at about the posterior third of the ramus. The inner face of the ramus above these foramina becomes slightly concave. The large external foramina are rather numerous and are situated at intervals of about 45 mm. They are situated posteriorly about as far below the superior edge as those of the internal series, and they retain that position anteriorly, not rising to a higher position, as is the case with those of the internal series. Posteriorly the internal face becomes slightly concave next the inferior border. The posterior part of the ramus is strongly concave on the inner side, and is thin walled. The base of the coronoid process indicates that it is flared outwards.

The condyle is a vertical oval tapering more gradually upwards than downwards. The superior border of the ramus is thin and curves strongly inwards, quite as Van Beneden has restored the corresponding part in the M. agrami. This condyle differs from that of the M. agrami in having a less transverse extent, especially on the inner side, and in lacking the transverse ridges and grooves described and figured by Van Beneden (Pl. ii, Fig. 10). This is the only part of the two animals which is present in both specimens; and the comparison indicates that the species are different.

I have probable vertebræ of this species, but I cannot yet associate them with certainty. A first dorsal was found in immediate contact with the posterior part of the ramus. This resembles considerably the corresponding vertebra of the M. agrami described by Van Beneden. It has lost its epiphyses, but if these were added, its anteroposterior diameter would be less than that of the latter, and there is not nearly so conspicuous a facet for the head of the first rib. This is very indistinct in my vertebra. A perfect humerus was also found near the position from which the second and third rami were dug out.

Until I know the proper relation of this humerus I will only describe it so far as to say that it has the proportions of that of Cetotherium, but that the tuberosity is not produced beyond the head, and the olecranar facet is not distinguished by an angle from the remainder of the ulnar facet.


Total length (subject to some correction on account of
a fracture).

vertical. .

97 Diameters at mental foramen


28 vertical.

90 transverse.

48 vertical......

120 transverse

61 vertical.

57 Diameters of centrum first dorsal vert. transverse.


anteroposterior. 31 Expanse of diapophyses...

170 From the Miocene marl of the Pamunkey river, Virginia.

Diameters at 500 mm. from distal end {
Diameters of condyle {

Stated Meeting, March 1, 1895.

Treasurer, Mr. PRICE, in the Chair.

Present, 15 members.

Dr. Richard A. Cleemann, a lately-elected member, was presented to the Chair.

Correspondence was submitted as follows:

Letters accepting membership from Dr. Richard A. Clee. mann, Philadelphia ; Mr. Richard S. Hunter, Philadelphia.

Letters of acknowledgment (143, 146) were received from the Franklin Institute, Engineers' Club, Wagner Free Institute of Science, Free Library of Philadelphia, Historical Society of Pennsylvania, College of Physicians, Numismatic and Antiquarian Society, Mercantile Library, Library Company of Philadelphia, Hon. James T. Mitchell, Hon. Henry Reed, Profs. John Ashhurst, Jr., F. X. Dercum, Henry D. Gregory, H. V. Hilprecht, J. P. Lesley, J. A. Ryder, Drs. John H. Brinton, W. W. Keen, F. W. Lewis, Morris Longstreth, Charles A. Oliver, C. N. Peirce, James W. Robins, W. S. W. Rusch. enberger, Henry Clay Trumbull, Messrs. R. L. Ashhurst, Henry C. Baird, Cadwalader Biddle, Lorin Blodget, Charles Bullock, S. Castner, Jr., C. H. Clark, Samuel Dickson, Patterson Du Bois, Philip C. Garrett, George Harding, William W. Jefferis, Benj. Smith Lyman, Franklin Platt, Frederick Prime, Theo. D. Rand, Julius F. Sachse, W. P. Tatham, Louis Vossion, Joseph M. Wilson, Ellis Yarnall, Philadelphia; Mr. Philip P. Sharples, West Chester, Pa.

A letter from Lorin Blodget, dated February 23, 1895, was read, in reference to a large collection of reports on Applied Electric Force, which he had obtained.

Accessions to the Library were reported from the K. Nordiske Oldskrift.Selskab, Copenhagen, Denmark; Académie R. de Belgique, Bruxelles; École des Mines, Secréteriat de S. A. S. le Prince Albert 1er de Monaco, Paris, France; U.S. Geological Survey, U. S. Department of Agriculture, Washington, D. C.; Artillery School, Fort Monroe, Va.

Photographs for the Society's album were received from Prof. James M. Hart, Ithaca, N. Y.; Mr. Robert N. Toppan, Cambridge, Mass.

A paper by Dr. F. Boas on “Salishan Texts” was presented by Dr. Brinton, who gave a brief synopsis of it.

Mr. F. Prime made some remarks on the relation of gold and silver, showing the output of those metals through a series of years, and the relative values of the two at different periods of recent history.

An extended discussion took place on Mr. Prime's commu. nication, partaken in by Dr. Morris, Dr. Greene, Dr. Horn, Prof. Snyder, Mr. Rand and others. Opinions were expressed on the bearing of the facts stated, on the merits of a bimetallic standard of currency, etc.

Dr. Greene spoke of the new element akin to nitrogen, which has lately been discovered, called Argon.

The death of Gen. William F. Raynolds, U. S. A., Detroit, Mich., was announced.

And the Society was adjourned by the presiding member.

Stated Meeting, March 15, 1895.,

Treasurer, Mr. PRICE, in the Chair.

Mr. Charlemagne Tower, Jr., a newly-elected member, was presented to the Chair, and took his seat.

Correspondence was submitted as follows:

Acknowledgments of election to membership were received from:

Dr. Herman Snellen, Jr., Utrecht, Netherlands.
Prof. William W. Goodwin, Cambridge, Mass.
Prof. Alpheus Hyatt, Cambridge, Mass.
Mr. Charles C. Harrison, Philadelphia.
Mr. Charlemagne Tower, Jr., Philadelphia.

Letters of acknowledgment were received from the Royal Society of Victoria, Melbourne (142, 144); Royal Society of New South Wales, Sydney (142, 144); Societas pro Fauna Flora Fennica, Helsingfors, Finland (145); Physico-Mathe. matical Society, Kasan, Russia (144, 145); K. K. Geologische Reichsanstalt, Vienna, Austria (145); Verein f. Erdkunde, Dresden, Saxony (145); Verein der Freunde der Natur. geschichte, Mecklenburg, Germany (142, 144, 145); R. Istituto Lombardo di Scienze e Lettere, Milan, Italy (144); Sir Henry W. Acland, Oxford, Eng. (145); Mr. F. Prime, Philadelphia (145); University of Wisconsin, Madison (136–141); Museo Nacional, Buenos Aires, Argentine Republic (142, 144); Société Scientifique du Chili, Santiago (145).

Letters of acknowledgment (143 and 146) were received from the Nova Scotian Institute of Natural Science, Halifax ; Mr. Horatio Hale, Clinton, Ontaria; Geological Survey, Ottawa, Canada; Laval University, Hon. J. M. Le Moine, Quebec, Canada; Canadian Institute, Toronto; Bowdoin College Library, Brunswick, Me.; Society of Natural History, Maine Historical Society, Portland, Me.; Prof. C. E. Iitchcock, Hanover, N. H.; Vermont Historical Society, Montpelier; Amberst College Library, Amherst, Mass.; Athenæum, Boston Society of Natural History, Massachusetts Institute of

« AnteriorContinuar »