KEMATODE GENUS PHYSALOPTERA. 1025 



The spicules are equal, straight, and pointed, each measuring 

 400 fx long by 32 /i broad. 



Host : Mus hrasiliensis. Stomach and small intestine. Brazil. 



Type males in bottle 4524, type females in bottle 4525, both 

 in the Vienna Museum. 



Von Drasche, in his account of this species, considers that the 

 number and arrangement of the bursal papillaj may be somewhat 

 different, as the material he worked with was too opaque. By 

 clearing the specimens in beechwood creosote, I was able to make 

 out two additional pairs of ventral post-anal papillse, viz. pairs 

 2 and 4, as well as the nature and lengths of the spicules. 



(7) PHYSALOPTERA ALATA Rudolphi, 1819. (Text-fig. 10.) 



Syn. Spi7'optera physalura Duj., 1845. 



The material examined consisted of some males and females 

 from Falco galUcus and some females from Falco pennattis ; both 

 lots from the Vienna Museum. 



These parasites have a somewhat slender body, whose cuticle 

 is very finely striated transversely ; the cuticle is either com- 

 pletely reflected over the lips or else leaves them quite naked. 



The cervical papillae are found from 75 to 100 jj, behind the 

 level of the hind end of the muscular oesophagus. The position 

 of the excretory pore appears to vary in that it was found in 

 some specimens to be very slightly posterior to the cervical 

 papillae, whereas in others it was as much as 200 yu further back. 



The lips are somewhat spherical in lateral view, and each 

 carries two terminal teeth ; the inner median tooth consists of 

 three large denticles, and is larger than the outer tooth ; the 

 outer tooth varies in size : in some specimens it is very small, 

 whereas in others it is almost as large as the inner tooth ; a 

 series of sizes can, however, be traced in different specimens, 

 showing the transitions of the smaller to the larger sized outer 

 teeth. Two somewhat slender external papillae are present on 

 eacli lip. 



The oesophagus is straight, and forms in the males about l/6th 

 and in the female 1/5-3 to 1/6-6 of the body-length. Its muscular 

 part is thinner than the glandular, and is encircled by the nerve 

 ring in its posterior quarter; it forms about l/9th of the whole 

 organ . 



Fetnale. 



The females from F. gallicus were all immature except one, 

 and this specimen was 21 mm. long and 540 ju thick; those from 

 F. pennatus were about 30 mm. long and 700 ju thick, and were 

 all mature ; the body is attenuated in its anterior half and also 

 slightly in its posterior third ; in the immature forms the tail 

 forms about l/45th of the body-length, but in the mature forms 

 it is slightly longer. 



The vulva opens practically level with the general surface, 

 and is situated relatively far back ; its position vai-ies slightly, 



