BY VERA IBWIN-SMITH. 241 



The lengths given by Linstow for males and females of Physaloptera antarc- 

 tica (27 mm. and 42 mm.) correspond exactly with the maximum lengths found 

 among these specimens, and with the lengths given by Stossieh for P. alba. The 

 size is exceptionally large for species parasitic in lizards and, as already pointed 

 out in the review of the Plvysaloptera of lizards (Irwin-Smith, Proc. Linn. Soc. 

 N.S.W., xlvii., 1922, p. 58), P. alba is probably a synonym. The flgnire of the 

 male tail given by Stossieh shows the characteristic pedunculated caudal papillae, 

 though not preanal papillae. And the host from which his specimens are re- 

 corded, Cyclodus boddaertii Dum., has been shown to be probably identical with 

 Tiliqua seineoides White, from which the present specimens were obtained. Lin- 

 stow's specimens were taken from a closely related host, Tiliqua occipitalis Gray. 



Fhtsalopteea antabctica var. lata. 



Most of the specimens in collection A are of somewhat shorter and stouter 

 build than those in collections B and C, and the body is unevenly proportioned, 

 being thickest in the posterior third, gradually attenuated towards the anterior 

 (Text-figs. 21-22). The structure and dimensions, otherwise, are very similar 

 in the two foi-ms, and the relative proportions of the different parts vary much 

 within the same limits, as will be seen by the comparative tables of measurements 

 below. The differences, which are best illustrated by Text-figs. 20-28, do not 

 seem to be of sufficient importance to warrant the classification of these speci- 

 mens as a new species. Therefore, I have grouped them as a new variety, lata, 

 of the species Physaloptera antarctica. The most notable differences are the dis- 

 proportionate thickness of the posterior end in var. lata, in all specimens, even 

 to the most immature, and the more advanced maturity of the smaller-sized 

 females, between 18 and 25 mm. long. 



Biagnos-is. — Denticular formation on lips (Text-fig. 29) very similar to that 

 in var. typica. Oesophagus one-eighth to one-seventh of the total body length 

 in the larger specimens, increasing to one-fifth in the smallest, slightly longer, 

 on the average, than in var. typica of corresponding size. Posteervieal papillae 

 a little further back from the junction of muscular and glandular oesophagus, 

 the maximum distance from the anterior extremity being .880 mm. (Text-fig. 

 24). 



Males 13 to 23 mm. long, average length 17.7 mm.; maximum diameter .53 

 to .80 mm. Bursa quite similar to var. typica, but relatively a little larger, its 

 alae .48 mm. wide; the three pairs of caudal papillae a little further removed 

 from the tail point, the cloacal aperture one-fourteenth to one-eighteenth of the 

 body leng-th from the extremity. Spicules similar in form and length to those of 

 var. typica, but of a slightly heavier build/ (Text-flg. 31). Genital system just 

 as in the other form. 



F,emales (Text-figs. 21, 22) 14 to 34 mm. long, average leng-th 24 m-n. ; 

 maximum diameter .80 to 1.45 mm. Tail more or less shrunken and distorted 

 in all the specimens; measurements only approximate, but apparently shorter 

 and more obtuse than in var. typica (Text-flg. 28) ; anus one-ninetieth to one- 

 sixtieth of the body length from its extremity. Vulva prominent, 1/2.5 to 1/4.8 

 of the body length from the anterior extremity, average distance 1/3.5. Egg's 

 quite similar. Genitalia grouped entirely behind the level of vulva; consisting 

 of the same parts as in var. typica, with the dichotomous division into four uteri. 

 Uteri, in all specimens, quite irregularly arranged, much twisted, intertwined 

 and spirally coiled; mostly on the ventral side of the body, and crowded towards 

 the posterior third, the last coils and the reeeptacula seminis always * within a 



