192 PROCEEDINGS OF THE ACADEMY OF 



himbars, and one caudal may serve as types. They indicate a species of less 

 size than any heretofore described, except perhaps the B. rostra t a now 

 living. They are about half the size of the vertebrae of Bala?noptera 

 prisca and, B. p a 1 cB a 1 1 an t i c a, and 3-5ths those of Eschrichtius 

 cephalus. 



The dorsal is a little longer than transverse width of centrum, and 2-5ths 

 longer than vertical width of the same ; the latter is therefore a depressed oval. 

 Inferior surface a regular arch from side to side. The lumbars have the 

 usual median keel, and the articular faces are not quite so transverse ; the 

 external planes are generally concave. The venous foramina in these are 

 so small as not to be noticeable. 



The articular faces of the caudal are a little more compressed and nearly 

 as deep as wide. The two inferior keels are very slight, the diapophysis are 

 not perforate, and the neural arch stands on 3-5ths length of the centrum. 



In. Lin. 



Length dorsal, 4 II 



Height articular face 3 6-2 



Width " " 4 3 



Width neural canal 1 4 



Lumbar length 4 11 



Height articular surface 3 11 



Width " " 4 2 



" neural canal 10 



Caudal, length , 4 



Height articular surface 3 9 5 



" to zygapophyses , 5 2 



Width articular surfaces 4 



Several cervical vertebrse show the characters of the genus and species. 

 They are all distinct, and their parapophyses and diapophyses have not prob- 

 ably been united, as the portions of them remaining are quite slender. 



The superficial dense bony layer of the ramus of the mandible, of which we 

 have specimens, is well developed, and nowhere fissured, and the nutritious 

 foramina small. The ramus moderately convex on both faces, much as in 

 the Balaenoptera p r i s c a , [Balxna Leidy), and like it, the nutritious fora- 

 mina were arranged in a series on each side of and close to the median 

 superior ridge. What distinguishes it from the latter is the presence of a 

 distinct median ridge, which separated from the inner face of the ramus by 

 a strong longitudinal groove. The nutritious foramina of the inner side 

 penetrate along the line of this groove. The size is about one-third the 

 same portion of the jaw of the B. prisca. Like the latter its inferior 

 margin is greatly decurved, and the outer side more convex than the inner. 



In. Lin. 



Length of fragment 15 



Depth inner face 2 



Circumference 5 2-5 



Remains of the mandibles of this species are not uncommon in the Miocene 

 region in the beds of streams. I have in similar situations dug out the 

 vomers of two whales whose size would correspond with the present. Bullae 

 of the periotic bones of small Balasnidae are not uncommon in the same 

 beds, and I suspect are mostly to be referred to this and the succeeding 

 species. 



The species appears to occur in the phosphatic deposit of the neighborhood 

 of Charleston, South Carolina, as I have a specimen of a lumbosacral ver- 

 tebra from that locality. It was among the toothless whales what the small 

 elephant of Malta was to the giant elephants. Our specimens have belonged 

 to individuals of not more than fifteen feet in length, and probably adult. 



[July, 



