SCHULTE, SEI WHALE. 397 



For purposes of comparison the proportional dimensions of these foetus are given in Table III. 



Table III. Comparative measurements of six foetuses of B. borealis. 



While neither Guldberg nor Collett state their mode of measuring, the very general corre- 

 spondence of percentages reckoned from their data with the linear proportions of this foetus 

 makes it highly probable that they too used linear measurements. The comparison of these 

 six foetuses shows no progressive change of proportion during the period represented save only 

 in the breadth of the flipper, which progressively diminishes, being least in the foetus of 1830 

 mm., the oldest in which this dimension is given, and here a more slender form is attained than 

 is found in the adult, according to Collett's measurements, 1 the length bearing the ratio to the 

 breadth of 1 : 4.7 while in the adult it is as 1 to 3.5 or 1 to 3.6 reckoned to the axilla. The 

 distance from rostrum to hump is in all cases within the limits of adult variation as given by 

 Collett, this dimension varying in five specimens between 61 and 68%. 



The measurements of six fetuses of B. musculus ( = physalus) ranging in length from 4 ft. 

 11 in. to 9 ft. 3 in. given by Burfield 2 makes possible a comparison with this species, and I have 

 added measurement of two foetuses of B. vellifera and one of B. sulphurea collected by Mr. R. C. 

 Andrews of the American Museum. I have quoted here only the percentage table of Burfield 

 and have used his points of measurement to facilitate comparison. 



This table indicates the relatively great fixity of the position of the anus in the several 

 species at the beginning of the last third of the body; it is in advance of this in B. vellifera alone 

 and there only to a very slight degree. Somewhat more variable, but still within narrow limits 

 is the position of the umbilicus just behind the middle of the body, being farthest caudad in 

 B. physalus and B. vellifera. B. borealis has the shortest rostrum, the longest pectoral limb 



1 Loe. at., p. 252. 



2 Burfield, S. T., Belmullet Whaling Station. Report of the Committee appointed to investigate Biological Problems incident to 

 the Belmullet Whaling Station. Report of Bri. Ass. Adv. Sci., Dundee, 1912, p. 145. 



