SCHULTE, SKI WHALE. 395 



of the upper abdomen. Since Carte and MacAlister no general account of the muscles in a 

 Mysticete has been given, and as their dissections were performed two weeks after the death 

 of their specimen, and their description in many places is extremely brief, it seemed desirable 

 to use this opportunity for reexamination of this topic. As to the abdomen, Weber in his 

 important study of the position of the alimentary canal in the Cetacea, has not touched upon 

 the conditions of the lesser sac, and the general literature affords but scanty information upon its 

 arrangement. Outside of these two main inquiries, I have recorded briefly the results of dis- 

 section, but have refrained from detailed study of many anatomical structures, which in a foetus 

 of this size were inconveniently small for dissection, and rather large for serial sections and 

 reconstruction. 



It has been the purpose of this report to record as objectively as possible the organization 

 of this foetus of a little studied species, and I have confined myself rather strictly to my subject. 

 In particular I have not attempted a collation or review of the literature, but have relied 

 largely upon the more recent studies in this field for comparison and interpretation, limiting 

 myself here again as far as possible to the works dealing particularly with the Balsenopterinse. 



Measurements. 



The dimensions of this foetus are given in the accompanying table I and their percentage 

 proportions in terms of the length from the tip of the rostrum to the notch in the flukes. While 

 the foetus, as has been said, was curved in an irregular spiral it was flexible enough to be 

 straightened and the measurements given were taken in this position with callipers. In the 

 case of a structure situated in the dorsal or ventral midline the measurement was taken to 

 its transverse plane thus avoiding obliquity in line of measurement and increase of dimensions 

 by following the curvature of the surface. The dimensions most dependent upon the mode of 

 measuring are of course the distances between dorsal points and in particular the total length, 

 owing to the curvature of the dorsum and the greater or less degree of flexion of the head. In 

 this foetus the linear length when the body is straight is 375 mm., but when the curvature of 

 the dorsum is included it amounts to 450 mm. 



Table I. Measurements of Andrews's foetus of Balcenoptera borealis. 



mm. % 



Total length, snout to notch of flukes 375 



Tip of snout to blow hole 45 12.0 



Tip of snout to eye 65 17.3 



Tip of snout to external auditory meatus L. 96 R. 88 Av 92 24 . 5 



Tip of snout to axilla 110 29.5 



Tip of snout to umbilicus 185 49.3 



Tip of snout to anus 257 68.5 



Tip of snout to hump 233 62.1 



Length of hump 16 



Notch of flukes to umbilicus 180 48.0 



Notch of flukes to anus 120 32.0 



Notch of flukes to hump 126 33.6 



Tip to tip of flukes 81 21 .6 



Anus to clitoris 



Anus to umbilicus 63 16.8 



Length of umbilicus 10 2.6 



