— 714 — 
of caudal papillae in males, size of the gubernaculum, and morpliology of the spiculés. 
Also 0. brevicaudatum has been reported from a frog in the Caucasus and it is a common 
parasite of A. fragilis in western Europe. The reported différence between these species 
in gubernaculum shape when viewed dorsally seems to be slight. The male tail in both 
species is relatively thick in the anal région and in specimens of O. brevicaudatum examined 
in the présent study a clear dorsal view of the gubernaculum was obtained only by dissec¬ 
tion of a worm. O. caucasicum and 0. brevicaudatum differ significantly only in the length 
of the spiculés. These were recorded as 380-400 pm long in O. caucasicum. In comparison 
spiculé length in O. brevicaudatum is usually recorded as being at least 1.0 mm and this 
was confirmed in specimens examined in the présent study. Only Chabaud & Campana- 
Rouget (1955) hâve observed male O. brevicaudatum with shorter spiculés ; they described 
a small worm from Alytes obsletricans of Southern France with spiculés 750 p long. The 
différence in spiculé length between O. caucasicum and O. brevicaudatum is nevertheless 
so great that désignation of these species as synonymous must await the study of more 
material from southwestern Russia. O. caucasicum may be a subspecies of O. brevicaudatum. 
3. Oxysomatium dollfusi n. sp. 
Description (fig. 4) 
Latéral alae narrow. Somatic papillae not numerous. Oral opening triangular, lips 
large. Cephalic papillae include six minute labial papillae and six cephalic papillae of 
which the submedian pair is markedly small. Anterior extremity of œsophagus with 
three tooth-like projections covered with thick cuticle. 
Male (holotype) : Total length 4.8 mm. Length of œsophagus 651 [Am (pharyngeal 
portion 51 [Am, posterior portion of corpus 463 (Am, isthmus 39 [Am, and bulb 98 (Am). 
Nerve ring 275 [Am and excretory pore 402 [im from anterior extremity. Tail 137 [Am 
long, tapering rapidly to long pointed terminal portion. Anus opening to exterior on 
the apex of a marked swelling. Latéral alae extending from 500-600 pm anterior to anus 
to mid-region of œsophagus. Caudal papillae markedly larger than somatic papillae. 
Posterior half of tail with two large subventral and two large subdorsal pairs of papillae ; 
subventral pairs often not aligned directly opposite eachother. Anterior half of tail and 
anal région with three pairs and one unpaired large papillae ; three pairs located subven- 
trally around base of swelling onto which anus opens, and unpaired papilla on anterior 
lip of anus. Unpaired papilla with cuticular wing-like supports as observed in the type 
species. Preanal région with 8-9 pairs of large papillae in two subventral rows ; the 4 pairs 
closest to the anus are close together whereas the other papillae are more widely spaced 
and the pairs are often not aligned directly opposite eachother. Spiculés prominent, 
192 [Am long, hook-shaped in latéral view, shaft divided into robust anterior third and 
more weakly chitinized posterior part supported by a wide membranous sheath. Distal 
end of spiculés sharply pointed. Gubernaculum prominent, 78 [Am long, with wide proximal 
end and sharply pointed distal end. 
Female (allotype) : Total length 5.0 mm. Length of œsophagus 780 [Am (pharyngeal 
portion of corpus 58 [Am, posterior portion of corpus 555 [Am, isthmus 55 [Am, bulb 112 pm). 
Source : MNHN, Paris 
