NO. 2131. NEMATODE PARASITES OF RODENTS—HALL. 109 



terminating in u corona radiata. Body subcylindrical, truncated 

 anteriorly. 



Jlale 5 mm. long and 300 fi thick. The large copulatory bursa is 

 obliquely truncate and prolonged in a conspicuous dorsal margin. 

 There are three groups of rays, the ventre- ventral being close to- 

 gether and parallel. The lateral groups of four rays include the 

 externo-dorsal and the lateral. The dorsal group branches twice on 

 each side, the rays therefore having four parts, of which the external 

 is the smaller, and the dorsal rays are bifid. Two long filiform 

 spicules. 



Female unknown. 



Host. — Thrichomys yachyurus {Isothric pacliyura) {fEchinomys 

 antricola: see comment below). 



Location. — Large intestine. 



Locality. — Barro da Kio Negra, Brazil. 



Molin makes this a species inquirenda on account of the lack of 

 female worms for description. He gives no figures and his discus- 

 sion of the dorsal rays, as transcribed above, is not entirely clear, 

 but it appears to be very close to the genus Strongylus at least, and 

 as the generic name Sclerostomum is a synonym of Strongylus and 

 without other standing, I have transferred the species to Strongylus. 



Von Linstow (1878) lists this species from Ecliinomys antricola., 

 apparently as a modern equivalent for Isothrix pacJiyura., but it ap- 

 pears that E. antricola is a synonym of Thrichomys apereoides. 



STRONGYLUS species. 



Synonym.. — Sclerostema species Morgan, 1868. 



SpecijiG diagnosis. — Strongylus (p. 108) : 



Host. — Castor fiher. 



Location. — Cecum and colon. 



Locality. — United States (Michigan?). 



In his work on the American beaver, Morgan (1868) says of the 

 worms found in this animal : "Also in the colon, and especially in the 

 caecum, sclerostema, male and female, species not known." There 

 seems to be nothing to be gained by speculating on this worm with- 

 out further data, and in view of the site of infestation I have re- 

 garded this as Strongylus. 



Genus TRACHYPHARTNX Leiper, 1911. 



Generic diagnosis. — Strongyleae (p. 107) : Oral aperture terminal, 

 surrounded by a corona radiata. The anterior third of the buccal 

 capsule is lined with a thick chitinous investment. The posterior 

 two-thirds of the buccal capsule is surrounded by esophageal muscu- 

 lature and is lined with a thin layer of cuticle bearing a large num- 



