39° 



DISCOVERY REPORTS 



O 05mm 



Figs. 27-32. Trigonocotyle prudhoei sp.n. from Lagenorhynchus obscurus. 27, the scolex; 28, part of the strobila; 29, cross- 

 section through part of longitudinal muscles; 30, cross-section through mature segment; 31, cross-section showing cirrus-sac 

 and vagina; 32, egg. 



Priapocephalus grandis Nybelin, 1922. (Figs. 33-41 ; PI. XX, 3-4). 



Hosts: Blue Whale {Balaenoptera musculus), Sei Whale (B. borealis), Fin Whale (B. physahis), Sperm 



Whale (Physeter catodon). 

 Localities : Saldanha Bay and Durban (South Africa) ; South Georgia ; Southern Ocean (56 40' 32' S, 



2 4° 33' W); Porto Pirn, Azores. 



The size of the specimens examined varies from 4 cm to 1 5 m. 24 cm. in length with a width varying 

 from 2 to 12 mm. The worms are in various stages of development, from immature to full-grown 

 individuals. There are also fragments of worms, measuring from 12 cm. to 5 m. 75 cm. in length and 

 2-12 mm. in width; some of these have scolices intact. These are typically acorn-like and are deeply 

 embedded in the mucous which exudes from the gut of the host. 



Fig. 33 shows the mode of attachment. It seems that there is a free space between the scolex and the 

 surrounding intestinal tissues of the host. The scolex bears a kind of collar, which possibly serves as a 

 supplementary organ of attachment. The maximum length of the scolex amounts to 7 mm., including 

 the collar; the corresponding width is 4 mm. 



The segments are wider than long (the length being about 1-5 mm.), and not craspedote. The body 

 is ivory white or yellowish in preserved specimens. 



The longitudinal muscles are very well developed. They are arranged in two rings, the outer one 

 being the less well developed. The inner one is composed of strong bundles, oval in transverse section. 

 The longitudinal muscles are variously developed in the same individual. In the juvenile forms or in 



