ORCELLA. 407 



indicated by a bulging of the inferior line as far back as the anus, and the back 

 corresponding to this area is arched but somewhat flattened, and concave over the 

 spinous processes. The dorsal flipper is somewhat falcate, its posterior margin being 

 nearly vertical and its upper border rounded and arching backwards and upwards, 

 but near its tip slightly downwards to the former. It lies between the umbilicus 

 and the vent, its hinder margin being on a line or nearly so with the anterior 

 margin of the vulva. It is also situated over the 27th to the 32nd vertebra, its 

 posterior margin being on a line with the hinder margin of the last-mentioned 

 vertebrae. 



Behind the anus, the breadth of the body rapidly decreases and is much com- 

 pressed from side to side, and it has a sharp dorsal and ventral margin which are 

 prolonged between the caudal flippers to the notch. The upper third of tins 

 portion of the side is marked by a longitudinal furrow, which is prolonged forwards 

 on to the trunk before the vent. The caudal flippers are rather pointed, and their 

 outer margins curve somewhat inwards. The longitudinal breadth of the base of 

 a flipper equals about half its length, and the distance between the tips is 6 

 inches. 



The vulva is a slit 1"'50 long, and on each side of it are the mammary slits 

 distant 0"'4il from the opening, their posterior estremities being only 0"'41 from 

 the hinder end of the vulva. The slits are 0""20 long. The anus is separated 

 from the vulva by a distinct peringeum 0"'41 long, which is the length of anal 

 puckering. 



The tail of the foetus from the vent backwards was bent forwards against the 

 left side of the belly, and the caudal flippers {t) were coiled round on themselves ; 

 the right bending downwards below the body and appearing on the other side, its 

 tip overlying the base of the left flij)per. The latter was bent inwards and applied 

 over the outside of the right flipj)er. The dorsal fin was bent downwards by its 

 base and lay over the left side of the back. 



The sides of the trunk from the pectoral flippers to the anus were thrown into 

 six great folds separated by deep svdci. These latter did not extend on to the back 

 nor on to the belly. Whatever explanation they may have, it is to be observed that 

 these great folds are confined to the part of the body which is bent. The sulci were 

 from 0"'50 to 0"'75 in depth. Besides these deep furrows the skin of the belly from a 

 short distance before the pectorals backwards to the vent and extending on to the sides 

 was thrown into long wavy convex ridges or folds about 0"'32 in breadth, separated 

 by very shallow depressions or sulci. On the sides they were shorter than on the 

 belly, and higher up they were restricted to the intervals between the deep sulci. A 

 few similar folds occur on the sides and back behind the vent, but they do not 

 extend any distance. The back is crossed by similar shallow folds which are most 

 pronounced behind the blow-hole and back of the head, but they do not reach the 

 sides of the head. 



The foetus with its membranes emptied of fluid, weighed 23ibs. 



The mammary gland of the foetus is 3-50 inches long. 



