300 



MR. H. A. BAYLIS AND LT.-COL. CLAYTON LANE ON 



Specific Diagnosis. 



Gnathostoma hlspidum Fedelienko, 1872. 



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

 posteriorly directed spines cover the whole of the body, the 

 anterior being comb-like, with seven points, and shorter than 

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



For list of hosts, see p. 304. 



3. Gnathostoma horridum (Leidy, 1856). 

 CJieiracanthus horridiis Leidy (1856, p. 53). 



Under the name of Gheu-acanthas hon-idiis Leidy described 

 from the stomach, presumably from the stomach lumen, of 

 Alligator mississij^j^iensis 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 w^ant of mention of any burrow^ing and the fact that the 

 host was a reptile and pred.itory are in favour of the belief that 

 these w^orms 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 hispid am. Regarding 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 hisj?idum and G. horrldmn are not, however, here 

 described as synon3aiis, 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 

 imperfectly described for one based on specimens which have 

 been investigated w^ith considerable thoroughness. No specific 

 diagnosis of G. horridum is attempted. 



4. Gnathostoma gracile (Diesing, 1838). 



Gheiracanthus gracilis Diesing (1838, p. 189), nomen nudiwi. 



., „ Diesing(1839, p. 225; pl.xiv. %s. 8-11; 



pL xvii, figs. 1-20). 

 V. Drasche (1882, p. 126; pi. ix. figs. 1-2). 

 [Not Echinoce2)halus gracilis Stossich (in Shipley and Hornell, 

 1906, p. 89).] 



Apart from its lengtli {vide Table VII. 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 



