300 Mil. H. A. bAYLIS AND LT.-COL. CLAYTON LANE ON 



Specific Diagnosis. 



Gnathostoma msPiDUM Fedclienko, 1872. 



Gnathostoma : nine to eleven rows of hooks on the head-bulb ; 

 postei-ioi-ly directed spines cover the whole of tlie body, the 

 anterior being couib-like, witli seven points, and shortei' than 

 the more posterior. The left spicule is twice as long as the right. 



For list of hosts, see p. 304. 



3. Gnathostoma horridum (Leidy, 1856). 

 CheiracantJnts horridxis Leidy (1856, p. 53). 



Under the name of Clie'ir acanthus horridus Leidy described 

 from the stomach, presumably from the stomach lumen, of 

 Alligator onississippie'nsis four females, 2.| inches long and a. line 

 and a half thick, with the body " cylindrical, incurved, posteriorly 

 subclavate, obtuse ; anteriorly covered with palmate plates 

 furnished with as many as eight spines and degenerating 

 posteriorly to simple spines." It is uncertain whether this last 

 expression implies that the spines reached the posterior end of 

 the worm. 



The Ava.nt of mention of any burrowing and the fact that the 

 host was a reptile and predatory are in favour of the belief that 

 these worms were really parasites of some host devoured by the 

 alligator; while, with the possible exception of size, there is no 

 characteristic by which this worm can be distinguished from 

 Gnathostoma hispiduin. Regaiding this last point it is probably 

 not disputable that a dead or dying worm commonly increases 

 in size as its muscles relax and decomposition begins. 



Gnathostoma hispidicm and G. horridum are noi:, however, here 

 described as synonyms, partly because no certain conclusion is 

 possible from the evidence, and partly because to do so would 

 necessitate the substitution of a name based only on females very 

 impei-fectly described for one based on specimens which have 

 been investigated with considerable thoroughness. No specific 

 diagnosis of G. horrid'um is attempted. 



4. Gnathostoma gracile (Diesing, 1838). 



Cheiracanthus gracilis Diesing (1838, p. 189), nomen mulum. 



Diesing(1839, p. 225; pl.xiv. tigs. 8-11; 



pi. xvii, figs. 1-20). 

 V. Drasche (1 882, p. 1 26 ; pi. ix. figs. 1-2). 

 [Not Echinocephalus gracilis Stossicii (in iSlupley and Hornell, 

 1906, p. 89).] 



Apa,rt from its length {vide Table V^II. p. 302) this nematode 

 has the following specific characters. The spines on the anterior 

 part of the body are leaf-like, with a maximum of five points, 

 one at the tip and the others along the lateral edges, two on 



