494 CETACEA. 



These recall to mind the moniliform vessel of Orca and the sac-like dilatations 

 of the arteries on the stomach of Orcella. In other instances the venous channels 

 send off a diverticulimi or side chamber (fig. 7), which occasionally is connected by 

 a narrowed orifice with a subsidiary sac. 



In a partially transparent transverse section of the umbilical cord (PL XXXVI, 

 fig. 11), the arrangement of the two main arteries and two veins is shown, and 

 besides, marginally and between the latter, a large vacuity, a probable remnant of 

 the urachus. Both arteries and veins have relatively thick and dense walls. The 

 urachus cavity is much tliinner-waUed, and interiorly I made out the remains 

 of minute and short papillae with an epithelial covering. Towards the peripheral 

 margin of the cord the gelatiae of Wharton is loose-meshed, and traversed by narrow 

 ellipsoidal channels. Although these approach the superficial glandular bodies, they 

 nevertheless do not seem to have any connection with them. 



Fcetus (PI. XXXI, fig. 1, and PI. XXXII, fig. 4).— The mouth of the foetus 

 was only partially closed, but its openness was probably a post-mortem result, 

 as the palatal surface had a longitudinal mucous ridge corresponding to a deep 

 groove in the middle of the flat prelingual surface. The outer aspect of both 

 jaws was raised into well-marked vertical ridges, and increasing in size from 

 behiad forwards and terminating in marginal papillary eminences, through which 

 the sharp teeth could be felt; and on the right side there were eighteen such 

 columns more or less visible on both jaws, and sixteen on the u]3per and 

 eighteen on the lower on the left side. The angles of the mouth and the 

 blow-hole were filled with a consistent grumous substance which appeared to 

 be cast and disintegrated epithelium, as a few broken nucleated epithelial cells 

 could be detected in it under the microscope. The pectoral flippers were laid 

 backwards against the sides of the body, and the free margin of the right was 

 slightly folded on itself. The dorsal fin was bent to the left side. The left caudal was 

 folded inwards against the under surface of the right flipper, while its tip was bent 

 over its own upper surface ; the tij) only of the right caudal flipper being folded in 

 a manner similar to its fellow. In the two foetuses which have come under my 

 olDservation the bodies have been marked by corresponding folds. Among the most 

 prominent of these is a deep fold which marks the position of the neck, occurring 

 half-way between the angle of the mouth and the pectoral flipper. It is deepest on 

 the ventral sm'face and extends up the side to nearly on a level with the eye. Two 

 other somewhat similar folds occur, one before and the other behind the anus, but 

 as they are due to the downward and forward bending of the caudal portion of the 

 animal they disappear shortly after birth. On the dorsal surface there are four large 

 folds which have been alike in both foetuses : a shallow transverse fold shortly 

 behind the blow-hole and corresponding in position to the gular fold ; a second 

 somewhat double fold stretching between the pectoral flippers ; and another occurring 

 at a third of the distance between the latter structures and the tip of the dorsal 

 flipper ; and a fourth half-way between the third fold and the dorsal fin. Behind 

 the dorsal fin there are seven to eight short transverse folds across the rather sharp 



