8 PROFESSOR FLOWER OA T RISSO'S DOLPHIX. 



the base of the pedicle of the arch of the sixth vertebra. This obviously represents 

 the neck of the seventh rib. 



There are eight pairs of sternal ribs, the last being very rudimentary. The first pair 

 articulate near the anterior extremity of the sternum, the second at the junction of the 

 first and second segments of that bone, the third at the junction of the second and third 

 segments, and the fourth and fifth to the hinder end of the third segment. The 

 remainder are not directly connected with the sternum. 



The various elements of the sternum are consolidated into a single bone, though 

 traces of its original formation out of three segments can be seen, and the primordial 

 median fissure is indicated by a slight longitudinal groove on its inner surface and a 

 small foramen near the anterior part of the first segment or manubrium. The entire 

 length is 11*2 inches. The greatest breadth of the first segment is 5 - 5 inches; the 

 least breadth, at the middle of the second segment, is 1*7 inch. The manubrium is 

 very slightly notched in the middle line in front; behind the attachment of the first 

 pair of sternal ribs its lateral borders expand as usual into rough triangular processes, 

 directed outwards and backwards. The hinder end of the posterior segment is deeply 

 notched 1 . 



The pelvic bones are slender and styliform, 4 - 9 inches in length. 



In general form the skull resembles the well-known figure of that of G. griseus in 

 Cuvier's ' Ossemens fossiles,' pi. 223. 



In plate 54 of the great work on the osteology of the Cetacea, now in progress, by Pro- 

 fessors Van Beneden and Gervais, are beautifully executed and evidently most faithfully 

 drawn figures of skulls, named respectively Grampus rissoanus and Grampus griseus, from 

 specimens in the collection at Paris, doubtless the type specimens 2 . There are certain 

 obvious differences between these two figures, especially in the size of the nasal bones and 

 the width and form of the rostrum ; but whether these are more than individual differ- 

 ences it would be hard to say, without a comparison of a large series of specimens. It 

 is to be noticed, however, that in all those points in which the figures differ, the present 

 specimen resembles G. griseus rather than G. rissoanus ; indeed the figure of G. griseus 

 (fig. 7) is so close a representation of it, both as to form and size, that, except for a 

 trifling difference in the shape of the anterior edge of the narial aperture, it might very 

 well have been drawn from it. 



In the flatness and breadth of the cranial part of the skull, and the wide expansion 

 of the maxillse above the orbits, it much resembles that of Globicephalus ; but it differs 

 in the rounded form and absence of elevation of the region behind the superior narial 

 apertures, in the marked convexity of the prsemaxilla? in front of these apertures, and 



1 This sternum appears narrower, in proportion to its length, than that of Grampus griseus figured by Van 

 Beneden and Gervais (op. cit. pi. 54. fig. 9), but otherwise does not differ materially from it. It closely 

 the sternum of Glohiceplialus. 

 Unfortunately the letterpress of this portion of the work has not yet appeared. 



