408 CETACEA. 



The papillae of the skin are about 0"'04 in length, and at their bases there is 

 a deposit of dark pigment, but the layer at their ends is colourless. They appear 

 to be generally distributed and not arranged in lines as in Flatanista. 



The fibrous layer of the skin is 0'''45 in thickness. 



Tabular view of body and visceral measurements of the foetus of 



Orcella brevirostris. 



Inches. 



From tip of snout to notch of tail, in straight line 33"75 



„ similar points following curve of back, alongside of dorsal fiu 36"25 



„ tip of snout to angle of mouth, in straight line 2'25 



From tip of snout to anterior margin of blow-hole following the curve 5*00 



From tip of snout to base of pectoral flipper 7'75 



Girth of the flipper at its base 4'50 



Pectoral flipper taken along its anterior border 8"00 



From tip of snout to anterior base of dorsal fin, in straight line 18"00 



From tip of snout to dorsal fin, following curve of back 20'00 



Distance from the snout to the umbilicus 16'75 



From the umbilicus to the generative orifice 4'50 



Length of external margin of caudal fin 7'75 



Length of internal margin of caudal fin, from base of notch 5"2-5 



Girth of head, at the blow-hole 15-75 



Circumference halfway between blow-hole and anterior border ...... 16'75 



Girth of body behind base of pectoral fin 15'75 



„ „ at the umbilicus 17"50 



„ at the root of the tail 475 



Depth through tail, half-way between anus and root of fin 3'50 



Total length of the intestines . 271-00 



The length of the small intestine 232-00 



The length of the large intestine 39-00 



General remarks on the skeleton. — The number of vertebrae appears to be 

 subject to little variation, 63 being the maximum in either species and 62 the 

 minimum. The ribs attached to the vertebrae are generally 12 in number, but 

 another pair may occur. In instances with the normiil number of vertebral ribs, 

 two pairs of floating ribs may be present, and in those animals with 13 true ribs one 

 pair of floating ribs may be found. 



In the foetus of O. brevirostris and in the adult male of O. fluminalis, the posi- 

 tion of the pelvic bones was ascertained. In the former they lay between the 35th 

 and 36th vertebrae, — that is, between two vertebrae bearing well-developed chevron 

 bones, and anterior to which was the 34th vertebra, with its chevron bones attached 

 also to the 35tli vertebra. In O. fluminalis, the greater part of the bones lay below 

 the 36th vertebra, but their anterior ends were opposite to the hinder part of the 

 body of the 35th. The chevron bones in this species also commenced between 

 the 34th and 35th vertebrae. If the vertebrae opposite the pelvic bones are sacral, 

 it is evident that in this genus, at least, the first chevron bones do not indicate the 

 beginning of the caudal vertebrae properly so called. In Grampus rissoanus a 

 similar relationship subsists between the pelvic and chevron bones, the latter occiir- 

 ring before the anterior ends of the former. If the two vertebrae lying above the 



