2 PROCEEDLNGS OF THE NATIONAL, MUSEUM vol.73 



lips, although there is a small chitinized buccal cavity surrounded by- 

 two, four, or six poorly defined lobes. There are other genera, as 

 Breinlia, Litomosa, and Hamulojilaria, the affinities of which with the 

 Filarioidea seem not to have been questioned, which possess this char- 

 acteristic. The type genus of the family, Thelazia, furthermore, has 

 the vulva in the esophageal region and has a filarioid type of tail 

 without the ornamentation or alae which are so characteristic of the 

 majority of the spiruroids. This character is not shared by Thyla- 

 conema, providing the male found with the type female is actually 

 the same species, but the habitat and probable life history of the 

 worm is more characteristically filarioid than is the case with Thelazia. 

 It seems to the writer that although the Thelaziidae are in many 

 respects intermediate between the Filarioidea and the Spiruroidea, 

 they can more conveniently be included with the former, as proposed 

 by Travassos (1918), than with the latter. 



The separation of a subfamily Aproctinae from the Filariinae, 

 proposed by Yorke and Maplestone (1926) on the basis of the 

 approximate equality or inequality of the spicules, does not seem to 

 the writer to 'be acceptable, since there are no other differential 

 characters to separate these groups. 



PROTOFILARIA, new genus 



Generic diagnosis. — Filariidae; Filariinae: Body slender and cylin- 

 drical, attenuated at the extremities. Head bluntly rounded, the 

 mouth without either lips or evident papillae, the minute oral tube 

 entering the esophagus a few micra from the anterior end. Cuticle 

 smooth, without striations or ornamentations of any kind. Esophagus 

 simple and cylindrical. Tail of female truncated, with a dorsoventral 

 cleft dividing it into two short lobes, and with the anus in the cleft 

 at the posterior extremity. Vulva near posterior end of esophagus. 

 Opisthodelphic and viviparous. Males with posterior end curled, 

 with short conical tail without either alae or papillae. Spicules 

 dissimilar and unequal, one spoon shaped, the other bluntly pointed. 

 Parasites of thoracic cavity of mammals. 



Type species. — Protqfilaria furcata, new species. 



PROTOFILARIA FURCATA, new species 



Figs. 1 and 2 



Specific diagnosis. — Protofilaria: Moderately slender worm; cylin- 

 drical, tapering for the anterior 1.5 to 2 mm. at the head end and 

 narrowing at the posterior end in a similar manner to a bluntly 

 rounded and slightly indented end in the female and to a short conical 

 tail in the male. Cuticle smooth, without striations or modifications 

 of any kind. Head bluntly rounded, without lips or evident papillae 



