224 



My specimens from the Rio Napo must be compared with birds 

 from Cayenne, before they can be referred without doubt to this 

 species. 



3. Description of Two New Species of Entozoa. 

 By W. Baird, M.D., F.L.S., etc. 



(Annulosa, PI. LTI.) 



In 1821 Nitzsch established a new genus of Nematoid Worms in 

 Ersch and Gruber's Encyclopaedia. This genus he named Hedruris, 

 from the two Greek words eopa, seat, and ovpa, tail, — a name by 

 which he intended to indicate the peculiar manner in which the 

 female is attached to the stomach of the animal in which it was 

 found. As yet there has been only one species described, Hedruris 

 androphora, which was first discovered in the stomach of the fresh- 

 water Newts, Triton cristatus and Lissotriton punctatus. The fe- 

 male is distinguished by having the caudal extremity swollen and 

 terminated by a suctorial apparatus, by means of which, and with 

 the assistance of a horny claw like the claw of a cat, it adheres 

 firmly to the coat of the stomach of its host. The tail of the male 

 terminates in a sharp curved point, provided with five or six papillae 

 disposed in a longitudinal series along the under surface. It is 

 always found spirally twisted round the body of the female, and 

 it is no doubt by means of these suctorial papillae that it keeps it- 

 self attached to the female. Dujardin, in his ' Hist. Nat. des Hel- 

 minthes,' hesitates where to place this genus, and arranges it in an 

 Appendix along with several others, the true position of which he had 

 not satisfactorily ascertained. Diesing, in his ' Systema Helmin- 

 thum,' places it in the same section as, and immediately following, 

 the genus Asca?'is, and considers, along with Nitzsch, that the species 

 androphora is identical with the Ascaris leptocephala of Rudolphi. 

 In the Collection of Entozoa in the British Museum are several spe- 

 cimens of a small Nematoid Worm, sent under the name of Ascaris 

 leptocephala to the National Collection by M. Siebold. If these are 

 correctly named by this last-mentioned naturalist, the species Asc. 

 leptocephala is a true Asca?'is, and quite distinct from the species from 

 which Nitzsch formed the genus Hedruris, a very good figure of 

 which may be seen in the ' Allgemeine Encyelopadie ' of Ersch and 

 Gruber, vol. vi. p. 48. 



A short time ago I received, through the kind attention of Sir W. 

 Jardine, a specimen of an Entozoon which he took from the abdo- 

 minal cavity of an Amphibian which has rarely found its way to 

 this country, the Siredon mexicanus. Upon examination I ascertained 

 it to be a female of a new species of this rare genus Hedruris. In 

 size it is about four times longer than the androphora ; it has a 

 larger head, and the body more distinctly striated across. This 

 species I have named Hedruris siredonis ; 'but as only the female 

 has been as yet discovered, I am unable to give a very detailed de- 

 scription of it. 



