NATURAL SCIENCES OF PHILADELPHIA. 



17 



the length from the muzzle ; dorsal line behind it smooth. S. tectirostris 

 Cope, 8. I a t i c c p s Gray. II, the dorsal a small conical mass, situated well 

 j)Osteriorly ; the dorsal line with several humps behind it; several cervicals with 

 complete cervical canal ; 8. tuberosus Co))e. Ill, the dorsal fin a small 

 conic mass situated three-fourths the length from the muzzle, the dorsal line 

 smooth behind it; the axis only, with complete cervical canal; {Floweriua 

 Lillj.) S b o r e a 1 i s Fisch. 



The S. TOBERosiTs m. ditters from the S. 1 a t i c e p s as above, and probably 

 in its five or six humps above the caudal portion of its vertebral column. The 

 latter peculiarity is not mentioned in authors' descriptions of S. 1 a t i c e p s, 

 and though its existence is not denied, it is probably wanting. I have hereto- 

 fore considered this whale as the latter species, and described it as such. — • 

 Proceed. Acad. Nat. Sci. Phila. 18G6, 297. 



The tinner whale, above mentioned as Sibbaldius tectirostris Cope, is es- 

 tablished on a nearly complete specimen of a young 9 ^^ the Museum of the 

 Academy. Its'leugth when fresh, in a nearly straight line from the end of the 

 muzzle to the emarginatioa of the flukes, is between 47 and 48 feet. This de- 

 pends on independent observations of several persons. The skeleton as pre- 

 served lacks a number of caudal vertebrae* and a few dorsals. Restoring those 

 that are at present wanting, from the obvious extent of interruption, and the 

 last caudals, according to Flower's estimates for the S. 1 a ti c e p s, we have 

 the following total length : 



No. 



Cervicals 7 



Dorsals \ 11 



Lumbosacrals* 16 



Caudals — diapophyses perforate 4 - 



Cranium. 



— diapophyses imperforate 10 J 



— no diapophyses 1 



10 



Restol-e^. 



41 7 

 3 6 



Total n 45 7 



The individpal is in the young stage, since not only are all the epiphyses of 

 the vertebrae separated, but those of the humerus also. According to Flower, 

 the coossification of the epiphysis of the humerus takes place when the animal 

 has developed somewhat beyond one-half the adult dimensions. This animal 

 may therefore be considered as being at least half grown, which renders a 

 length of 70 — 80 feet probable for the adult. The present specimen was a fe- 

 male, according to those who had seen it in the flesh, and who described to 

 me the mamma; and the vulva. In its larger dimensions it thus exceeds the B. 

 1 a t i c e ps, and especially the B. t u b e r o s u s, as the latter is adult at about 

 the size of this young specimen. 



The atlas has not yet reached the Museum. The axis presents below no 

 surface adapted to a tubercuhim atlantis. The median portion of the anterior 

 face of the centrum presents a low conic projection, the processus odontoideus. 

 The di- and parapophyses are united distally, embracing a large ring, whose out- 

 side longitudinal diameter is two-thirds the transverse diameter of the centrum 

 of the same. The neural arch presents no spine, but a pair of lateral promi- 

 nences like rudimental zygapophyses. The parapophyses of the remaining 

 cervicals are long, exce[)t on the seventh, where they are almost wanting. The 

 diapophyses are long in all, longest and decurved on the seventh, where it 



* All are in possession of the Academy, but those alluded to are yet in a. compost heap 

 and unfit to handle. 



1868.J 2. 



