CESTODE AND NEMATODE PARASITES. 89 



MAEGARITIFERA VULGARLS AND PLATAX TEIRA. 

 Ascaris meleagrinae, LINSTOW. 



Part II. of this work, p. 99. 



Platax teira is a new host for this species. The stomach of Platax teira, one of 

 the " sea-bats," contained numbers of Octopuses entangled with Lumbriconereids and 

 Eunicidse. This Nematode also lives in Batistes mitis and B. stellatus. 



Echinocephalus gracilis, n. sp. 



The following account of this new species is due to the late Professor M. STOSSICH : 

 " In the pearl oyster, Margaritifera vulgaris, there lives the larva of a Nematode, 

 which LINSTOW recently ascribed to the species, Echinocephalus uncinatus, a species 

 created by MOLIN for the form living in the Adriatic Trygon, but in comparing these 

 with some of the examples of E. uncinatus from the Adriatic, it is evident that they 

 are entirely different, and neither belong to the species of LINSTOW or of MOLIN. 

 I therefore create a new species, Echinocephalus gracilis, with the following 

 diagnosis : 



"Body about 12 millims. long, caudal end hooked and twisted; the head is 

 surrounded with a spherical swelling of the cutis, covered with six transverse rings 

 of hooks, each containing some 40 to 50 hooks ; these hooks resemble closely those of 

 certain Echinorhynchus, and consist of a large half imbedded in the skin and of a free 

 blade ; they gradually increase in size from the first to the sixth row. The mouth is 

 surrounded by six lips, the dorsal and ventral are the largest and are truncated at 

 their outer end, the four lateral have their free end distinctly crenated. 



" Habitat : Margaritifera vulgaris, in the adductor muscle." 



STEGOSTOMA TTGRINUM, GATHER. 



The stomach of this fish contained the feet of Gastropods and remains of Pleuro- 

 branchi. 



Acanthocheilus nidifex, LIN TON. 



Allied species occur in Mustelus vulgaris, M. laevis, Scyllinm catulus, S. stellare, 

 S. canicula, and other Elasmobranchs. 



