306 MR. H, A. BAYLIS AND LT.-COL. CLAYTON LANE ON 



ELAPHOCEPnALUs Molin, 1860. 



KlaphocejyJialus Molin (1860, p. 343). 



Genotype: Elafhoceplmlus octocorimtus Molin (1860, p. 344). 



v.Drasclie(1884.p. 113; 

 pj. iii. figs. 21-23). 



This genus and species, based on a single female from Ara 

 ]_Psittacus\ macao, are characterized by tlie possession of four 

 cervical sacs which are withont the internal processes found in 

 Ancyr acanthus. As in that genus, there are four freely-projecting 

 ex-ternal appendages, each of Avhich, however, 2:>ossesses an 

 external process shorter than itself. The cuticle of the body 

 carries closely-set spines. 



Whether Ancyracanthus piimatiJidKS and Elaphoce2:>halus 

 ■ostocoriiutus do or do not belong to the Gnathostomidai can only 

 he ascertained after further investigation, but it is not impossihle 

 that the structures just mentioned correspond to the ballonets 

 and cervical sacs of the Gnathostomince. If this be so, the 

 <lifference between the subfamily and these two forms presumably 

 lies in ;\n exuberant development, in the latter, of the ballonets, 

 iniconfinei by a stout overlying covering. Jn the forms 

 unquestionably belonging to the subfamily such confinement 

 within a uniform head-bulb is complete in Gnathostoma and 

 Echinosej^lialns, less complete in Tanqua anomala and T. diadema, 

 a.iid least so in Tanqua tiara, in which last the prominences 

 corresponding to the four underlying ballonets are sometimes 

 strikingly distinct. It is not difficult to imagine tluit further 

 exuberance and external subdivision or indentation of the cuticle 

 covering the ballonets might well produce those external and 

 internal modifications which have been described in these two 

 genei'a. 



jSTote. 



Our best thanks are due to Mr. T. Southwell, formei'ly Director 

 of Fisheries for Bengal, Bihar and Orissa, for supplying i;s with 

 much of the material upon wdiich the work has been based, 

 especially as regards the genus Eckinocephalus. 



As regards the nomenclature of the hosts, w-e are indebted to 

 Mr. Oldfield Thomas, F.R.S., for verifying and correcting the 

 names of all the malnmals n:entioned in the jiaper; and to 

 Mr. C. Chubb, Dr. G. A. Boulenger, F.R.S., and Mr. G. Tate 

 Regan, F. U.S., for performing the s;vme kind ofiice in the cases of 

 birds, reptiles, and fishes respectively. 



For the preparation of some excellent serial sections ^ve are 

 indebted to the skill of Mr. Cecil Gunns, of the Zoological 

 Department, Imperial College of Science. 



For all errors and omissions we accept full responsibility. 



The figures ha.ve all been drawn to scale with the aid of the 

 Abbe camera lucida. 



The type-specimens of the species described as new are in the 

 British Museum (Natural History). 



