101 289 



Pedalionidæ. 



The family comprises the three genera Triarthra, Tetramastix and Pedalion. 

 The males of the peculiar genus Teframastix first described by Zachahias 1898 

 (p. 132) and later by Rousselet (1906, p. 431) are unknown. 



Plate has described the male of T. hreviseta, but the description is very short 

 and no figure is given. Wesché has figured and described a male, which he refer.s 

 to T. longiseta, but whatever Wesché has found, it is very difficult to understand 

 that it is a male of the genus Triarthra he has observed. 



Triarthra longiseta Ehrbg. 

 Tab. XV, flg. 1. 

 Rousselet (1903, p. 176) 

 has observed the male but there exists no description). 



Wesché (1902, p. 325, PI. 17, fig. 1 a, b) has perhaps seen the male. 



"The head is well defined, and its limits are marked by several folds of skin. The body 

 is broad and stout. The foot is well separated from the body, without toes, but with two short 

 setæ on the orifice of the penis, which goes down to the extremity of the foot. . . There is a large 

 brain with a conspicuous sub-circular eyespot. Four powerful muscles are attached to the 

 Ijrain and cilia... The dorsal antenna is connected with the brain by a flexible tutjc. The 

 lateral antcnnæ are well marked, and have the usual ta])ering gland, noticeable in tlie female. 

 There is no trace whatever of a digestive system. The lateral canals are well marked, and 

 the contractile vesicle large. The skin is thick, but flexible. A large spermatheca tapers down 

 to the end of the foot, which practically forms the penis. Size 70 — 90 /<. Time: February." 



Description. Body elongate, attenuated behind, soft, hyaline, two or three 

 times slightly constricted. The wheel-organ a closed ciliary wreath without any 

 tongue-like projection ventrally. In the middle of the disc a peculiar broad rectan- 

 gular projection of a proboscis-like appearance; it is covered with a coating of very 

 short hairs and, near its base, bears the two semiglobular red eyes, each with a lens. 

 There is a brain, but no retrocerebral organ; neither dorsal nor lateral antennæ 

 have been observed. Only a large pyriform testis is found, containing two sorts of 

 spermatozoa and ending in a long "penis'" tube ciliated in its interior. During the 

 pairing-process the body behind is acuminated; in this and in the following species 

 the penis is really only the acuminated hindpart of the body. Near its opening this 

 latter bears two small chitin-pieces, which can be folded in and out; there is no 

 ciliary wreath round the opening, but a little above it two strong sensitive hairs. 

 Round the testis two prostata glands. A faintly developed system of longitudinal 

 muscles has been observed, but no conspicuous transversal muscles. The body is 

 extremely flexible, when not compressed much, more globular than the drawing shows, 

 but during the mating process still more attenuated behind. The body contains very 

 many oilglobules often arranged in a half circle round tlie testis. Size male 80 //, 

 female about 170. Time 15/V 21. 



As mentioned above Wesché has described and figured the male: according 

 to the figure, with regard to the opening for the penis, it may be regarded as pos- 



