58 NEMATODES OP THE GENUS PHYSALOPTERA, 



As noted above, this species is probably identical with Physaloptera antarc- 

 tica. The few measurements given accord with those for Linstow's species, and 

 both worms are recorded from species of the same genus of host. The figures 

 for the male tail, given by the two authors, show a close agreement in the 

 general shape of the bursa, and the area on it covered by the cuticular gi-anu- 

 lations. Both writers note the length of the stalks of the external papillae, a 

 feature which is also well shown in the two figures. In the figure of P. alba, 

 precaudal papillae are missing, but these papillae are easily overlooked. Phy- 

 saloptera from the same host, which I have examined recently and found to 

 agree in most pai'ticulars with the description of P. antarctica, have the three 

 pairs of caudal papillae stalked, as shown by Stossieh. The females examined 

 are also found to possess a four-branched uterus. Neither Linstow nor Stossieh 

 makes any mention of the female genital system, but I have placed the species 

 in this group (A), on the evidence afforded by the worms now in my collection, 

 of which a full description will be published later. 



B. Species with uterus divided into two branches. 



Physaloptera leptosojia (Gervais) Seurat, 1917. 



Synonyms. — Strongylus leptosomus Gervais, 1848; Fraipont, 1882; ? Physalop- 

 tera chamaeleontis Gedoelst, 1916. 



External labial tooth cuneiform, truncated, and provided with a little rounded 

 button at the extremity. Internal teeth vei-y distinct, bicuspid. Internal denti- 

 cular border much reduced, interrupted by indistinct elliptical spots. Post- 

 cervical papillae slightly asymmetrical, the left longer. Muscular oesophagus re- 

 markable for its brevity. Caudal extremity of female digitiform, elongated. 

 Vulva not salient; vestibule and reservoir very elongated (3.125 mm.), unpaired 

 trunk of uterus fairly long (500 ^), dividing into two parallel branches, 1.6 mm. 

 long, each of which continues as a uterus extending nearly to level of anus. 

 Caudal pores opening at posterior third of tail, in a slightly sunken elliptical 

 area, bounded by a thin cuticular border. Male spicules very unequal. Caudal 

 bursa elongated. Cloaca bounded by two salient lips with smooth surface. Cuti- 

 cular processes of circum-cloacal region armed with spines, and arranged in 

 longitudinal rows. Caudal pores just beyond middle of tail. For details of 

 caudal bursa see figure. Measurements as given in table. 



Physaloptera chamaeleontis Gedoelst, 1916. 



External labial tooth triang-ular. Internal "fourehette" absent. The two 

 extremities of the female equally attenuated ; tail conical. Vulva slightly pro- 

 minent; vestibule and reservoir 3.2 mm. long, unpaired trunk of uterus 1.5 mm. 

 long, dividing into two branches 2 mm. long, each continuous with a uterus. 

 Maximum thickness of male body in the posterior half, gradually attenuated in 

 front. Spicules very unequal. Caudal bursa 1.44 mm. long. Circum-cloacal re- 

 gion provided with a regnalar longitudinal series of chitinous denticles, extending 

 nearly to the middle of the tail. For arrangement of caudal papillae see figure. 

 Measurements as given in table. 



As will be seen from the tables of measurements, this species agrees so 

 closely in all its dimensions with P. leptosoma as to suggest that it is a synonym. 

 This assumption is strengthened by a comparison of the descriptions. The 

 structure and proportions of the female genital systems are about the same; in 



