ASPLANCHNAD.E. 13 



tlie male arc very small ; and the lateral canals have the vibratile tags arranged in a 

 straight line on either side. The creature is so -wonderfully transparent and empty, 

 that it is difficult to see it even with a hand-lens, although ,;\| inch in length. The 

 hind dorsal corner of the body is somewhat prolonged into a sort of third hump, and 

 darts out stiff and obvious (as do the lateral arms) when the head is retracted. The 

 opposite ventral corner is prolonged, to a blunt point, and is the sheath of a long 

 protusile penis. In one specimen I saw tags in which no ciliary motion was visible. 

 Wliat appears to be an atrophied oesophagus and stomach hangs freely in the body-cavity, 

 between the head and the above-named dorsal hump. Mr. Gosse has seen the male in 

 utcro. 



Length (male), xjL inch. Habitat. Birmingham (P.H.G., and T.B.) : Clifton 

 (C.T.H.). 



AsrLANCHNA AMPHOEA, Huclson, sp. nov. 



SP. CH. Body, of female, conical, icith one dorsal, and tiro lateral humps ; eye 

 single; rami uilh long curved simply pointed ends, and a stout hook at the middle of 

 the inner edge of each, not serrated ; contractile vesicle not large, expanding to very 

 much less than half the body-cavity ; vibratile tags above forty on each side, and 

 arranged in straight lines ; ovary a narroiv ribbon ; male ivith two lateral humps. 



Professor Leidy kindly sent me this Asplanchna, in 1887, preserved in spirit ; and 

 I am indebted to Mr. G. Western for many hving specimens. The female closely 

 resembles Ebbesbornii ; but the posterior extremity is almost conical, whereas in 

 Ebbeshornii it is ventrally prolonged into a blunt curved hump. The two lateral 

 humps, also, are nearer the middle of the body, and the ephippial egg is covered with 

 dotted scales. Mr. Rousselet lately called my attention to the fact that the vibratile tags 

 are crowned with a row of fine hairs, with a long one at each corner. Mr. G. Western 

 has seen the male in utcro. 



Length, ^'^ inch. Habitat. Philadelphia (Leidy) ; near London (Westei-n). 



Asplanchna tkiophthalma, Daday (207). 



SP. CH. Female humpless ; head truncate ; eyes three — two smaller a little below 

 the dorsal margin, one greater cervical ; vascular system, as in priodonta ; ovary, a 

 transverse ribbon. Male humpless. 



Dr. Daday courteously sent me his memoir on this Asplanchna, which he found " in 

 the great pool nearMezo-Zah." It distinctly differs h:ora priodonta in the position of the 

 two smaller eyes, and in the truncate head. Dr. Daday has given a drawing of the 

 vibratQe tags showing each crowned with a row of fine hairs. 



Length. About -h inch. Habitat. See above (Daday). 



A. HELVETICA, Imhof (179). I can see no difference between helvetica and priodonta ; 

 but M. de Gueme (173) separates them, because helvetica has only sis " denticula- 

 tions " on the inner margui of each ramus, and its supplementary tooth, or uncus, is 

 " strongly arcuate " ; while "the figures and descriptions" oi priodonta give it more 

 than six denticulations, and a "scarcely arcuate" uncus. I have examined many 

 specimens of priodonta, since my attention has been called to these points, and I have 

 always found six denticulations in each ramus (PL XXXIII. fig. 2) ; and that the appa- 

 rent curvature of the uncus varies much with pressure, with the point of view, and with 

 the individual. Tlie wide dispersion of helvetica throughout Switzerland, Northern 

 Italy, Austria, North and South Germany, Auvergne, Russian Lapland &c. &c., makes 

 it highly probable that the two species are identical. 



