23 Mr. P. H. Gosse on Asplanclina priodonta. 



specimen which appeared hkely to be a male ; but it soon died, 

 and I was uncertain. Soon after, I saw the developing young in 

 a pregnant female, that seemed different from the ordinary em- 

 bryos ; and in hope that this might be a male, T isolated the pa- 

 rent. At length I had the satisfaction of seeing it born, and of 

 finding it exactly the same as the one I had taken, but widely 

 different from the female. Another was produced in the same 

 evening from another parent, likewise under my eye. The ejec- 

 tion, though occupying only a few seconds, was not so instan- 

 taneous as I had observed it in the Walthamstow species. Both 

 of these new-born males I placed with several females, but no 

 intercourse took place, and 1 again isolated them for the night 

 with sufficiency of water ; but in the morning one was dead and 

 the other dying. Judging from these, the first I saw must also 

 have been newly born. 



The length of these specimens was yy^ inch. They had a 

 general agreement in outline with the female. But the outlet 

 corresponding to the vagina was at the very bottom of the ventral 

 side, which ran down to a point, while the dorsal side was rounded 

 off (see figs, e &/ ). At the base of this tube was a globular 

 sperm-sac, with a short thick penis in front (see/) ; the whole 

 nearly suiTOunded by a delicate glandular mass. The place of 

 the stomach was occupied by a long sac having a slender neck 

 originating from the front part of the head-mass, and at the bot- 

 tom broadly attached to the sperm-bag. This whole organ was 

 filled with minute granular matter except three or four clear glo- 

 bular bladders : the sperm-bag showed a structure very similar. 

 The principal muscles agreed with those of the female. The tor- 

 tuous threads and their plexuseswere represented by twothickened 

 glandular bodies extending from the head-mass to the foliaceous 

 substance surrounding the sperm-bag. The drawing of the head- 

 mass was taken from a dying specimen, and probably needs cor- 

 rection ; the three eyes however were present, situated as in the 

 female, but no trace of jaws was discernible, even on pressure ; nor 

 any crop nor true stomach. These were very active, swimming 

 rapidly about, and scarcely still an instant. On one or two oc- 

 casions I observed one of the males with a slender process pro- 

 truded to a considerable length from the sexual orifice, and ad- 

 hering to the glass by its tip ; moving round on it as on a pivot. 



The stomach of the female is frequently occupied with animals ; 

 the svaaWer Anurcecp, as A. aculeata, curvicornis {^.) and stipitatai^), 

 which are abundant in the water, seem to constitute its chief 

 food. I have taken one with the species last named in its 

 stomach, which after about an hour was ejected and swam about 

 bs lively and apparently uninjured as ever. In one I saw several 



