168 BAL^NOPTERID^. 



" A bone which, from its general appearance, texture, and surface, 

 I presume mxist be the sternum, especially as there was no other which 

 could have represented this portion of the skeleton, presents most 

 anomalous characters. It is very flat on both surfaces, a little more 

 than 1" in thickness, of an irregularly oval form, being larger on one 

 side than the other, and slightly produced at Avhat I suppose would 

 be the posterior border, and notched in the anterior. It is only 5f " 

 in its greatest diameter (transverse), and 4" in the other direction. 

 Certainly the condition of the edges gave evidence of a bone incom- 

 pletely ossified ; but its very small size, especially in the antero- 

 posterior direction, for a Phi/salus of the dimensions of the one 

 under examination, is very remarkable. 



" The body of the hyoid I was unable to find ; but the stylo-hyals 

 are slightly curved, compressed, with a thick convex border, and a 

 thinner concave border, rather larger at one end than the other ; 14" 

 in length, 4:j" in greatest width, and 2" in thickness ; presenting, in 

 fact, the usual form seen in the genus Physcilus. The scapula and 

 arm-bones had also the ordinary form ; the former is 21" in height, 

 and 35|" in breadth ; the acromion 7|" long, and 3^" in breadth ; 

 the coracoid 2|" long ; the glenoid fossa 10|" by 7". The humerus 

 is 17" long, 7| ' in longest diameter, and 20" in circumference at the 

 middle. The radius is 27" long, 6" in breadth at the upper end, 

 4^" at the middle and 7|" below, and 3" thick at the middle. The 

 ulna is 25" long, 7" across at the top, Sg" at the middle (and 2" in 

 thickness), and 5|" at the lower end. The circumference of the two 

 bones together at their middle is 20|-". The metacarpal bones are 

 long for the size of the animal, being respectively, beginning at the 

 radial side, 6", 8", 6|", and 4^" ; whereas the same bones in the 

 adult Common Fin-Whale in the Antwerp Zoological Gardens are 

 4|", 6", 6", and 4|" ; and in the specimen in the Alexandra Park 

 4|-", 6", 5", 3f". The phalanges are long, and rather different in 

 number from those in the specimens of the Common Fin-Whale which 

 I have examined, being 4, 5, 5, and 3 in the several digits, com- 

 mencing on the radial side with No. II. In the Antwerp Phy solus 

 they are 2, 7, 6, and 3. But, as in both cases they have been arti- 

 ficially articulated, much importance cannot be attached to these 

 numbers. 



" This skeleton differs in some respects from any other that I have 

 seen, nor can I identify it with any published description sufficiently 

 detailed for exact comparison. That it belongs to the genus Physalus 

 as above defined there is little question. The only difficulty is in 

 the form of the sternum. It must be remembered that the indi^ndual 

 was young, and the bone, being slow of development, is subject to 

 considerable variation in form during growth, and also, when fuUy 

 grown, to great individual diversities of form. It scarcely seems 

 advisable, therefore, on account of this one specimen to modify the 

 generic diagnosis as regards this bone, though such a course might 

 be necessary if a very small oval, transversely elongated sternum were 

 found characteristic of the adult animals belonging to the species. 

 I think that there can be no question that this character, together 



