DURING HIS SOJOURN IN THE WESTERN PACIFIC. 543 



II. SuBFAM. Phyllocanthina van Ben. 



1850. Recherches (7), p. 127. 



A. Bothriis quatuor, singulo uncinalis 2, magis curvatis, bifurcatis armato. 



9. Genus. Acanthohothnum van Ben. 



'B. Bothriis quatuor, singulo uncinali.s 4, simplicibus, parum curvatis armato. 



10. Genus. Onchobothrium Rud. 



11. Genus. Calliobothrium van Ben. 



III. SuBFAM. Phyllorhynchidea van Ben. 



1850. Recherches (7), p. 14-i. 



A. Bothria nulla. 



12. Genus. Abothros Welch. 



B. Caput bothriis instructis. 



13. Genus. Rhynchobothrium Rud. Caput bothriis duobus oppositis parallelis 



aut apice convergentibus. 



14. Genus. Tetrarhynchus Rud. Caput bothriis quatuor, binis oppositis, capiti 



parallelis. 



Familia(6): Diphyllidea van Ben. 



1850. Recherches (7), p. 158. 



Caput versatile bothriis duobus lateralibus et infra marginem anticum utrinque 

 rostello horizontali protractili, apice armato munitum. 



15. Genus. Echinobothniim van Ben. 



A point of interest in the Helminthology of Elasmobranchs is the minuteness of 

 the parasites. As Dr Orley records, the tape-worms which infest the largest sharks 

 such as Carcharias and Heptanclius never surpass 10 cms. in length. As a rule the 

 size of the Entozoon is inversely proportional to that of its Elasmobranch host. Both 

 the small .size and the comparative rarity of the parasites point to the fact that 

 Elasmobranchs suffer but little from the presence of Cestodes, though doubtless the 

 Teleosteans in whose bodies for the most part the worms pass through its cystic stage 

 sufifer considerably. When however they do occur in Elasmobranchs they are often met 

 with in great numbers, and this is especially the case with the genus Calliobothrium 

 which is sometimes found in enormous numbers on the spiral valve. 



In that helminthological mine of information P.-J. van Beneden's " Recherches sur 

 la Faune Littorale dc Belgicpio, Les Vers Cestoides,'" the author establishes the genus 



' Mem. Ac. lieliiiqitr, xxv. 18-50. 



