70 



A. E. SHIPLEY 



The maie is not quite 1 cm. long, and 1 mm. in dlameler. — 

 MÉGNiN (abstracted). 



Habitat. — Air sacs of Larus glaucus Brunn, from Polar Seas. 

 The number ol tlie rings in this species is unfortunately omitted 

 from the account, but judging from the somewhat vague figure, 

 there are about 110. The length of the female is given as H cm. but 

 the tigure of tliis animal (( de gi-andeur naturelle » measures only 

 about 3,5 cm. The body was crowded with eggs. 



The larval stage is unknown, it may reasonably be expected that 

 its host is a fish. 



12. — POROCEPHALUS MEGACEPHALUS Baird (1) 



Synonym. — Pentastoma megacephalum Baird. 



DiAGNOsis. — ((.Female : body yellowish white, somewhat depres- 

 sed and termina ting anteriorily in a large thick club-shaped head. 



The dorsal surface is 

 depressed at the edges, 

 rounded and very pro- 

 minent in the centre 

 and transversely ridg- 

 ed. The ventral surface 

 is more flattened, ridg- 

 ed and v\Tinkled, with 

 the mouth in a hollow 

 dépression, surrounded 

 by four strong brown 

 simple hooks. The part 

 of the body immediately 

 beneath the head is very 

 strongly ridged trans- 

 versely, each of the first 

 six ridges being wavedly wrinkled. The length of the whole body 

 is about 11 lines. The head is 5 Unes broad, and the middle portion 

 of the body about 3 1/2 lines, diminishing in size towards the tail. 

 The oviduct is very long, the portion outside the body being 2 

 inches in length. 



(1) Proc. Zool. Soc, part XXI, ISiiS, pp. 21 and 22. 



Fig. 15. — Porocephalus megacephalus BsiTd. — 

 A, female in natural size ; B, head of maie 

 X 2. Aftcr Baird. 



