86 Snail-Leeches. 



brane- — which one may often see in the form of a thin particle 

 of jelly adherent to bodies taken out of ponds — and attach 

 themselves to the under surface of the mother. And a very 

 curious sight it is to see the young fellows popping out their 

 heads on all sides, accompanying their cc maternity ;j wherever 

 she goes, remaining thus tied to their mother's apron strings 

 for six or seven weeks in some cases. 



I do not know an instance of any other animal so low in 

 the scale of creation that exhibits so great care for its young 

 ones. Amongst Crustacea, some of the Isopoda have been 

 observed to exhibit much affection for their young brood, 

 receiving them, after temporary wanderings, back into the 

 cavity fitted for their protection ; and the female Coccus deposits 

 her eggs, and then dies as she sits upon them. But not all the 

 species of Glos&iphonidce are " sitters." Some, instead of de- 

 positing their eggs on foreign bodies, retain them, as I have 

 already remarked, within the cavity formed by the folding- 

 inwards of the sides of the abdomen. This is the case with. 

 Gr. hioculata, and G. liyalina. The number of young ones 

 which the snail-leech produces varies ; as few as three and as 

 many as thirty may be contained within each vitelline mem- 

 brane. The clusters, or ova, also vary considerably in number. 

 So far as I have observed, the large gelatinous species Glossi- 

 plionia tessellata is the most prolific. Some deposit their eggs 

 as early as April, others in June and July. Upon G. hioculata 

 the smallest of the family, is almost invariably found a curious 

 cup- shaped plate. It is situated on the front part of the animal, 

 about the twelfth segment. What its use may be I have no 

 idea ; it open out at the upper sitrface, and is quite charac- 

 teristic of this species (PI. 2, Fig. 4). It is very common to 

 see a group of infusoria parasitic upon this membranous plate 

 (Fig. 8). Several species have been described as belonging to 

 this family, but there is much uncertainty about some of them. 

 I will now give descriptions of the following, all of which, per- 

 haps, are true British species : — Glosslphonia complanata, G. 

 hioculata, G. tessellata, G. marginata, G. hyalina, G. vermicata, 

 and G. eachana. I am well acquainted with all except the 

 two last named. 



G. complanata.' — Body, when at rest, almond-shaped, nar- 

 rowing suddenly at the anterior extremity ; back with four or 

 five rows of conical transparent papillce or tubercles — the two 

 largest and most distinct forming- a row on cither side the 

 medial axis of the body — and having two dark lines down its 

 middle; these two medio- dorsal lines, which are constant in 

 this species, although sometimes indistinct, are cither unin- 

 terrupted throughout the entire length of the body, or an even 

 succession of spots; rings, about sixty in number; eyes, six 



