284 DR. H. LYSTER JAMESON ON 



'\'Tylocephalum dierama (Report V. p. 59). Intestine of il//y?i'o- 

 hatis maculata. Diameter of head '6 nnn. 

 TylocephaliDn kuhli (Report V. p. 72). Intestine of Trygoii 

 kuhll. Head apparently about "5 nnn. in diameter. 

 fTi/Iocephalum uarnak (Report V. p. 76). Intestine of ^'ryc/oii 

 uarnak and Trygou walga. Head apparently about 1 mm. 

 in diameter. 

 ^fCephalohothrium aetohatidis (Report V. p. 44). Spiral valve 



of Aetohatis narinari. Diameter of head "5 mm. 

 ^■fKystocephalus translucens (Report V. p. 46). Intestine of 

 Aetohatis narinari. Diameter of head '4 mm. 

 *-Eniochobothrium gracile (Report V. p. 64). Intestine of 

 Nhinoptera javanica. Head appears to measure about 

 "4 mm. in diameter. 

 *f I'iarabothrium javanicnm (Report V. p. 67). Intestine of 

 Bhinopter a javanica. Head 1 mm. bi'oad. 



To these may be added two forms described by Mr. Southwell 

 (41a), viz.: — 



Cephalohothrimn abruptum, from the spiral valve of Pteropilatea 



micrura. Head 1*2 mm. broad. 

 Cephalohothrium variahile, from the intestine of Prisies cuspl- 

 datus. Head 1 mm. broad. 



The forms marked * occur in hosts which are known to feed 

 on pearl- oysteis. Those marked t I have been able to examine 

 through the courtesy of Dr. Shipley. It is impossible not to be 

 struck with the resemblance between the heads of some of the 

 above species and the parasites which Herdman associates with 

 })earl-formation. Compare, for example, the head of Cephalo- 

 lothrinia aetobatidis, iignred in Part V. (Cestoda) plate i. figs. 1-4, 

 Avith some of the figures of Tylocephalwm ludificans in the chapter 

 on Pearl- Production (Part V. Pearl-Production, plate iii.) or 

 the heads of Tylocephala [Tetragonocephala) as figured on the plate 

 of Part III. (Parasites), and in the article on Cestodes in Part Y. 

 (pi. V. figs. 76-7), with soiae of the figures in the article on the 

 parasites of the Pearl-Oyster in Part II. Or, again, compare the 

 section of TyJocephalum ludificans from the pearl-ovster shown 

 on PI. XLYI. fig. 58, with the head of T. uamali, PI. XLVII. 

 fig. 65, drawn from one of Dr. Shipley's slides, as a representative 

 of the genus Tylocephalum, taking into account the diiference 

 that in the foi-mer the myzorhynchus is withdrawn within the 

 collar, whereas in the latter it is fully protruded. Or compai'e 

 PI. XLVI. fig. 59, a section of T. ludificans from the pearl- 

 oyster, with the head of Cephalohothrmm aetobatidis, from one of 

 Dr. Shipley's slides shown on PI. XLYII. fig. 66. Similarly, 

 compare figs. 58 & 59 with the worm shown in figs. 61 & 62 on 

 PI. XLVII., also from Aetohatis narinari (the final host of Seurat's 

 larva) J. I think the worm shown in figs. 60-64 is quite probably 



X It is strange that the oyster-eating habits of this Ka}- do not seem to have 

 been recorded in those L'evlon researches. 



