8 PROCEEDIN-QS OP THE NATIONAL. MUSEUM vol. 80 



larity. However, the number of submedian head papillae for U. 

 macro'phaUos, as given by Baylis, is four, while the number in the 

 other members of the genus in which it is known is eight. H. varani 

 and n. hipinnatuni are too poorly described for conclusions to be 

 drawn as to their possible identity with either of the above forms. 

 Having only the present inadequate information as to the variation 

 of the body length, the length of the spicules, and the number of tail 

 papillae, one can not consider that any two of these species are 

 identical. The above four species have one point in common, the 

 relatively thick left spicule. On the other hand, H. gouldi, H. seti- 

 ferwn, and H. onchocercum have in common a narrow, delicate left 

 spicule. 



After a study of the literature and the three available species, it 

 appears necessary to emend slightly the generic diagnosis as given 

 by Yorke and Maplestone (1926), as follows: 



HASTOSPICULUM Skrjabin, 1923 



Generic diagnosis. — Filariidae: Mouth elongate dorsoventrally, 

 more or less rectangular in outline, surrounded by a heavy cuti- 

 cular elevation, which may or may not give the appearance of 

 epaulettes, depending on the distinctness of the cuticular and sub- 

 cuticular tissues; paired, lateral liplike organs projecting from the 

 outer margin of the circumoral elevation, and smaller papillate 

 structures sometimes present at the base of the latter ; paired, lateral 

 organs (amphids) and at least four, usually eight, submedian papil- 

 lae ; esophagus composed of a shorter, anterior, muscular portion and 

 a longer, relatively wide, glandular, posterior portion. Vulva an- 

 terior, in the esophageal region ; opisthodelphous ; oviparous. Anus 

 in the female more or less atrophied. Male with a single testis, 

 spicules unequal, the left much longer than the right; tail sur- 

 rounded by a pair of caudal alae supported by pedunculated papillae. 



Type species. — Kastospiculum varani Skrjabin, 1923. 



KEY TO THE SPECIES OF THE GENUS HASTOSPICULUM 



For the purpose of separating the species described in this paper 

 from those previously described, the following key is given : 



1. Left spicule as wide as riglit 2 



Left spicule not so wide as right 5 



2. Male 135 mm. to 140 mm. long; left spicule 4.4 mm. long, right 



spicule 660/4 long; female unknown varani 



Male less than 100 mm. long ; left spicule not more than 2.75 



mm. long, right spicule not more than 510/^ long ; female known 3 



