248 ME. H. A. BAYLIS AND LT.-COL. CLAYTON LANE ON 



cuticle tends to cause their terminations to lie at the bottom of 

 funnel-shaped depressions. Strong oblique ventral muscles occupy 

 the whole distance between the cloacal opening and the anterior 

 termin;ition of the alas, and may depress part of the preanal 

 surface iiito the semblance of a sucker. There are two subequal, 

 delicate, tapering spicules without flanges. 



In the female the tail, when seen from the side, has the dorsal 

 surface convex and the venti-al concave, and there is a notch on 

 its ventral surface just anterior to the tip. The vulva lies near 

 the middle of the body, whence the muscular vagina runs 

 anteriorly before dividing into two thinner-walled uteri, the one 

 running towards the head and the other towards the tail. The 

 egg-shell is thin, colourless, oval, with fine external stippling, 

 a clear space separating it from. the granular contents. 



The worms ai^e found attached to, or buried in, the wall of the 

 stomach of tortoises in Europe, Asia, and Africa, and possibly 

 America. 



The subfamily contains only the genus S'jnroxys. 



Suljfamily Diagnosis. 



Spiroxyin.^. 



Gnathostomidfe : without head-bulb, ballonets, or cervical sacs ; 

 lips wide, with a narrowed base and a trefoil-shaped pulp, and 

 having the internal cuticle of the middle lobe much thickened, 

 the point of the thickened portion projecting anteriorly as a sharp 

 tooth ; caudal cuticle of the male expanded into lateral alse and 

 a preanal vesicular swelling and bearing two pairs of ventral 

 papillaj, one in front of and one behind the cloacal opening, and 

 nine pairs of la,teral papillae of which six ai'e postanal and three 

 preanal, and which, by reason of the cuticular distensions, fre- 

 qviently appear to lie at the bottom of funnel-shaped depressions; 

 spicules delicate, tapering and subequal ; vulva near the middle 

 of the body; the vagina running anteriorly; the two uteri 

 opposed; ova with thin, colourless, stippled shell, from which the 

 unsegmented granular contents are sepiai'ated by a space. 



Generic Diagnosis. 



SPIROXYS* Schneider, 1866. 



S2nroxys Schneider (1866, p. 125). 



Spiroxis Schneider (1866, p. 29) [misprint]. 



Spiroptera (in part) Rudolphi (1819, pp. 25 & 242). 



'iAscaris{in part) Rudolphi (1809, p. 193; 1819, pp. 25 & 242). 



? Fhysaloplera (in part) Leid}^ (1856, p. 53). 



The genus has the charactei'S of the subfamily. 



Genotype: Spiroxys contorta (Rud., 1819). 



* For \ey to species, see p. 249. For measurements, see Table I., p. 253. 



