556 



DISCOVERY REPORTS 



Bolbosoma capitatum (v. Linstow, 1880) 



A single immature specimen, probably referable to this species, occurred in the 

 stomach of a slender-beaked dolphin {Steno rostratiis) taken off the West African coast, 

 not far from Cape Verde. 



Bolbosoma hamiltoni, sp. n. 

 (Figs. 12-14) 



A single male and several females of this form occurred in a fin whale [Balaenoptera 

 physalus) at South Georgia, February 18, 1926. A single specimen was also found, 

 together with B. brevicolle, in a blue whale {Balaenoptera muscuhis) at 

 South Georgia. The species is very closely related to B. capitatum 

 (v. Linstow, 1880), but the spines on the " bulb " are smaller and much 

 more numerous than in that species. The proboscis-hooks are also more 

 numerous, and their roots are less broad and flat than in B. capitatum. 



The length of the male is about 60 mm., the females attaining about 

 64 mm. The maximum thickness of the male is 2-05 mm., that of the 

 female 27 mm. The diameter of the "bulb" is 378 mm. in the male 

 and 3-51 mm. in the female. The length of the proboscis (in the female) 

 is about 0-9 mm., and its maximum diameter (near the base) about 

 o-6mm. It bears apparently 26 longitudinal rows of hooks, each 

 containing seven or eight. (In B. capitatum there are only i8(-20.'') pig. 12. Bolbosoma 

 rows of hooks.) The more anterior hooks are slender and sharply liamiltotti. Male 

 pointed, and their tips show a slight tendency to curve outwards, while (-^) ^^^ female 

 the blade is as long as the root. The length of the largest hooks (i.e. the ^ "^ "" 

 second and third in each row from the anterior end), measured in a straight line from 

 the tip to the point of insertion, is about 0-09 mm. in a female specimen. The roots 

 of these anterior hooks have a very slight "heel", or suggestion of an anterior root. 

 More posteriorly the hooks become gradually shorter, stouter and blunter, and the 

 blades become shorter than the roots. The most posterior hooks are very small and 

 thorn-like, with scarcely any root. 



The spines on the bulb are very numerous, and the largest of them (those in the 

 posterior rows) are less than o-i mm. in length, whereas in B. capitatum the posterior 

 spines are about 0-24 mm. long. 



The posterior testis of the male is just in front of the middle of the body. The eggs 

 are spindle-shaped, and measure o- 11 2-0- 137 mm. x o-o27-o-03 mm. 



