226 38 



ensemble que j'appelle l'organe copulateur. Le pénis est placé sur la face dorsale du pied. 

 Lorsqu'il est complètement retiré son extrémité arrive juste à la racine des doigts du pied 

 et est protégée par deux petits bourrelets circulaires. .\u iiicnu' niveau, de chaque côté, dé- 

 bouchent les canaux latéraux du .système excréteur.« 



Description. Maie of almost the same form as the female, but in front almosl 

 cylindrical, only tapering behind. It is more elongate, narrower than the female, but 

 curved on the dorsum like this sex. The cuticula is very thin, hyaline and extremely 

 flexilile, it is tliickest dorsally and in the middle part of the body; the forepart can 

 be withdrawn, the posterior part only in sligliter degree. Tlie wheel-organ formed 

 exactly like that of the female; some stronger hairs on two elevations on tlie disc. 

 No frontal hood. The brain is large, perhaps not always faintly bilobed behind, and 

 with a nerve to the dorsal antenna; no lateral antennæ have been obsei'ved. Two 

 red eyes as in the female. Of the alimentary canal onh' a connecting band between 

 the testis and wheel-organ; Weber regards this band as being of muscular substance. 

 The excretory organ consisting of two canals with three vibratile tags; no contrac- 

 tile vesicle; Weber has seen the opening of the canals on both sides of the penis; 

 I have failed to see them. Testis large pyriform, suspended by means of fine liga- 

 ments. The copulatory organ formed as in Diglena grandis and in close accordance 

 with the admirable description of Weber. Two very small prostata glands. Above 

 the testis a globular mass. Four transversal muscle bands; four pairs of longitudinal 

 bands and at all events one pair of slanting muscles from the base of the foot to 

 the dorsal antenna. Two foot glands. No oil globules. Size of the male 140/; of the 

 female 150 /<. 



Diglena catellina is here as evervwhere an extremely common animal. In May 

 it was found in the algæ carpets almost in every pond ; and many eggs were laid in 

 parts of these carpets which were brought into the vessels. The males v\'ere rather 

 common, though always rarer than the females. 



Diglena giraffa. Gosse. 



Tab. I, flg. 9. 

 Description. Male extraordinarily slender, tapering posteriorly, straight, of an 

 almost incredible hyalinity. Hexible in a degree which has perhaps never been ob- 

 served and moving with an enormous speed. 1 never succeeded in making camera 

 drawings of it, but I got some measures when the animal was fully stretched out, 

 and could study the internal structure rather exactly. The form differs very much 

 from that of the female, having no marked neck and no tumid abdominal part, the 

 whole body being almost hairshaped, only a little thicker in front than behind; the 

 toes are verv" long, straight, the cuticle is soft, without any longitudinal folds, the 

 whole animal bluish hyaline almost quite invisible. The wheel-organ as in the female, 

 but without any frontal hood, insufficiently observed. Brain pearshaped with nerves 

 for the dorsal organ; two red eyes placed very near each other. Of the alimentary 

 canal only a band. Lateral canals with three vibratile tags; no contractile vesicle. 



