284 



Memoirs of the Indian Museum. 



[Vol. VII, 



Fig. 18. — Contracaecum incurvum. Tail of male ; later- 

 al view. 



for about 2 mm., has the cuticle raised into pronounced longitudinal ridges, inter- 

 rupted by transverse grooves at intervals of 0-03 mm. The spicules are equal in 



length (4*1 mm.) and have broad alae, 

 except for a short distance at the tip. 

 The caudal papillae are all rather small 

 and sessile. There are about 15 pairs 

 of preanal papillae, those near the clo- 

 aca small and close together, the more 

 anterior gradually becoming larger 

 and wider apart. There is also a pair 

 of double adanal papillae, and four 

 postanal pairs, of which two are ven- 

 tral and two lateral. 



The host in which the adult form of this 

 species has been commonly recorded is the 

 sword-fish, Xiphias gladius} and the worm ap- 

 pears to be very widely distributed and to 

 attain a large size. Linton (1901) has also 

 recorded immature stages, probably of this 

 species, from several other fishes In the pre- 

 sent collection there are included some encapsuled larvae from the mesenter}' of Nandus marmora- 

 tus and Wallago attu, and from the body-cavity and peritoneum of another (unnamed) Gsh, which show 

 the same oesophageal structure as the specimens from Histiophorus, and are perhaps to' be referred to 

 the same species The largest of these larvae is about 33 mm. long. The oesophagus does not yet 

 exceed 3 mm. in length, and the oesophageal appendix 05 mm. The intestinal caecum is already of 

 considerable length. The lips are not yet formed, so that it is impossible to confirm the determination 

 by a study of their stuctm'e. 



Contracaecum tricuspe (Gedoelst, 1916). 



This species was described by Gedoelst from an African heron. We have to 

 record its appearance at Calcutta in the Indian darter or snake-bird (Plotus melano- 

 g aster). 



Contracaecum engonium, sp. nov. 



(Figs. 19, 20.) 



A single male specimen was collected from the black stork (Ciconia nigra). It 

 measures 13 mm. in length and 0*57 mm. in maximum thickness. The head 

 measures 0*19 mm. in diameter, and is constricted off from the body. The interlabia 

 are simple and undivided at the tip. The dorsal lip (fig. 19) is rounded anteriorly 

 and carries a pair of double papillae. The pulp roughly follows the shape of the lip, 

 but is indented on its anterior edge. Each lip is provided with a pair of flattened 

 processes springing from the internal surface and projecting anteriorly like two small 

 horns at the shoulders of the lip. The muscular portion of the oesophagus measures 



1 Histiophorus gladius, though probably related, not distantly, to Xiphias, is not the same fish, and appears to 

 be a new host. 



