THE NEMATODE FAMILY GXATIIOSTOMID.E. 



297 



and the sessile pair behind the cloacal opening. He found also 

 small worms, possibly young individuals of the same species, 

 5 lines long *. 



Diesing (1839, p. 222) in describing Cheir acanthus rohustus 

 noted its closeness to Gnathostoma sjnnigerum, but, accepting as 

 correct Owen's description of the head and spicule, he, with 

 diifidence, separated the two forms. It is probably not doubted 

 at the present time that Owen and Diesing were working on the 

 same species. In his subsequent description of Diesing's material, 

 V. Drasche (1883, p. 126) described four pairs of large and three 

 pairs of sessile papilla?. 



Under the name of Cheiracaiitlias siamensis Levinsen (1889) 

 described a single poorly preserved immature female nematode 

 which had been removed from an abscess in the breast of a young- 

 native woman in Siam. He was able to deal with external 

 characters only. The distribution and shape of the spines on the 

 head and body were identical with those of Gnathostoma sjy'ml- 

 yerum. In his Latin synopsis {L c. p. 325) he uses the expression 

 " Corpus ill partem, caadalem trilobatum desinet." His figure of 

 the ventral aspect of the tail sliows, however, that what actually 

 existed was merely a slight compression of the lateral outline of 

 the tail posteriorly to the anus, a condition which does not 

 correspond to the idea conveyed by the term " three-lobed." 



Leiper (1909, p. 70) has described a male of Gnathostoraa 

 siamense which, as the context indica,tey, came from a sub- 

 cutaneous swelling in a native of Siam. Tlie lips were large and 

 fleshy, measuring "1-5 by 0-5 mm.'' [?0-15 by 0-05 mm.] and 

 each bearing two papilhe with a median protrusion between them. 

 The cephalic hooks measured 0*015 by 0'005 mm. Spines covered 

 the anterior four-lifths of the bod}^, the most anterior having 

 three digitations, the most posterior one only. The ejaculatory 

 duct was 1-5 mm. long. Later Leiper (1911, p. 18 ; 1913, p. 281 ), 

 after re-examining Diesing's original examples of Cheiracanthus 

 rohustus (which, however, he speaks of as having come from the 

 leopard), reaches the conclusion that the male form obtained from 

 man corresponds exactl}^ witli the male of Cheiracanthus rohustus, 

 which, he remarks, " is acceptedly the same as Gnathostoma spini- 

 gerum.'" In no respect, indeed, do the forms from the sub- 

 cutaneous tissue of man <lifier, except in the matter of maturit}^ 

 from those from the stomach of Felidae, but must be considered 

 merely as individuals which have strayed into an unnatural 

 habitat in an unnatural host {cf. Leiper, 1909, p. 80). 



Cheiracanthus socialis Leidy (1859, p. 53) was found in cavities 

 •in the thickened stomach-wall of the mink (Mustela vison). There 

 is in its size, in the character of its lips, head and hooks, in the 

 shape and distribution of the spines on the body, in the internal 

 organs, so far as described, and in the genital papillae, nothing to 



* Owen did not describe the males as 5 mm. long and the females as twice that 

 length, nor the tail of the female as trilobed {vide Stephens, in Fantham, Stephens 

 and Theobald (1916, p. 385);. 



