THE NEMATODE FAMILY GNATHOSTOMID^. . 



271 



Specific Diagnosis. 

 Taisi-qua diadema Baylis. 



Head-bulb divided in the adult into two swellings, situated 

 dorsally and ventrall}^, each containing two ballonets. Head 

 retractile within the cuticular collar, which forms a prepuce-like 

 sheath. Yulva in middle third of the body. Uterus with two 

 opposed branches. 



Habitat: "intestines" (? stomach) of a Hwake, Helicops cmgu- 

 latus, in Brazil. 



Doubtful Species of Tanqua. 



ASCARIS SPHiEROCEPHALA E,ud., 1809. 



Rudolphi (1809, p. 188). 



On account of certain resemblances between the characters of 

 this species, as described by Rudolphi, and those of the worms 

 of the Gnathostomid group, we mention it. here for the stike of 



