97 285 



in an elongated mass fi-om the I'ronl. At its lower extremity a very larf^c rL-ddish-hlack 

 granular mass seems to concentrate into a dark-red eye on the ventral side. Four powerl'ul 

 muscles are attached to the hrain and cilia. The antcnnæ are as in the female. There are some 

 minute glands below the orifice of the penis on the ventral side. A curious circidar gland, 

 connected with the hrain by a long muscle, may have some relation to the contractih' vesicle. 

 The penis, which is rather long, is ciliated and kept retracted. On pressure being a|)i)lie(l il 

 was protruded through an opening which corresponds with the orifice of the fool in the 

 female. I was able to see the spermatozoa individually in the spermatheca." Size male 127/*. 

 Time: Marsh. 



Description. Body peculiarly sliaped, trunk fish-formed, resembling that of 

 the female; as in the female without any conspicuous lorica, but with the same 

 longitudinal Iveels and furrows along the dorsal edge of the trunk; here the skin 

 seems fliicker than in other parts of the body; a very short, truncate foot wliich 

 can be wholly retracted into the skin. The whole animal very hyaline. The wheel- 

 organ consists of a ciliary wreath, witliout the two styli characteristic of tlie female; 

 on the disc which is ratlier flattened and not protusile as in this sex, stand a number 

 of bunches of long bristles; also the whole alimentary canal is absent. The brain 

 is large with a large red eye; behind this a large, reddish-black mass. Two nerves 

 to the dorsal antenna and two lateral antennæ. Lateral canals with three or four 

 vibratile tags; no contractile vesicle. Testis very large, almost globular with a peculiar 

 form; two prostata glands and above them two peculiar irregularly formed cells, 

 connected with the testis and moving together with it and almost incessantly. A 

 peculiarly shaped foot hardly ever seen during swimming; it is undivided and has 

 no toes; dorsally is the opening for the penis which, when fully stretched out, is 

 much larger than the foot, this being placed laterally, only as a small appendix. 

 The testis opens into a ductus seminalis which is coated with cilia and ends in a 

 bunch of cilia. Above the testis many oil globules. There are five transversal musc- 

 les, running from the dorsal keels downwards; four pairs of longitudinal muscles 

 for the wheel-organ and two short muscles for the foot. The males resemble young, 

 newly born females very much. Size of male 80 /(, of female 360 /<. Time 1/V 21. 



As will be seen, there is not the best harmony between Wesché's description 

 and mine; Wesché has observed the place of the antenna; what he regards as a 

 gland connected with the brain and what he supposes to have some relation to the 

 contractile vesicle, I do not know; his description of the penis differs very much 

 from what I have seen. 



Gastropus stylifer Imh. 



Tab. XIV, fig. 2-3. 

 Description. Body elliptical, attenuated behind with a rather thick lorica: 

 hyaline, no strongly marked colours. A dorsal plate carrying medially and anteriorly 

 a shield-like structure with parallel sides and an acute point. The wheel-organ 

 which is wholly retractile, consists in a ciliary wreath, contouring a disc which 

 carries some bunches of cilia and as far as I have been able to see one single 

 digitiform thick fleshy antenna. A large brain upon which I have been unable to 



D. K. U. Vidensk. SelsU. SUr., naturv. og ni.Tlhem. Alii., 8. R.-ckki;, IV, 3. 38 



