724 RECORD OF CURRENT RESEARCHES RELATING TO 



was often dry for a long period every day; as a rule, the larger 

 examples were found in older, and the smaller and younger specimens 

 in younger animals, but tliis was not always the case. As their name 

 implies, the MalacohdelUdce have a body of extreme softness ; when 

 young they are, except in the region of the sucker, of very much the 

 same breadth all along their whole extent. The oral apertm-e is 

 placed at the anterior end, and is in the form of a transverse cleft ; 

 the pharynx is intensely white, and may be seen through the trans- 

 parent integument ; the intestine is much narrower than it, and is of 

 a brownish or reddish-yellow colour ; the proboscis is of an opaque 

 white, and on either side of the pharynx there are cerebral ganglia, 

 which are small, and white or yellowish in colour. 



The form in question seems to have been known to O. F. Miiller 

 (' Zoologia Danica,' 1779), and has since been examined by De Blain- 

 ville (1827), Blanchard (1845), and Van Benedcn. The result of Von 

 Kennel's inquiries is the confirmation of the Nemertine character of 

 the form ; the surface of the body is completely ciliated, the proboscis 

 is of the typical form, the vascular and excretory organs are of just 

 the same type as in the other Nemertinea, and the nervous and 

 muscular systems point to the same conclusion ; the anal nervous 

 commissure has been already found in Pelagonemertes. When, how- 

 ever, we come to inquire as to the position which it should take in 

 this group, we find it necessary to form a new family ; the Nemer- 

 tinea, hitherto divided into three families, contain one, the Enopla 

 (Tremocephalida), in which the proboscis is armed with spines, the 

 dermal musculature confined to two layers, and the nervous system 

 inferior to it ; and two, Rhocmocephalida and Gymnocephalida, in 

 which there are three dermal muscular layers ; between the two inner- 

 most lies the nervous system ; and in these — Anopla — the proboscis 

 has no armature of S2)ines : the fourth, and new family, may be thus 

 defined : — 



MalacohdelUdce. — No armature of spines to the proboscis, the 

 dermo-muscular layer arranged in an external, circular, or an internal, 

 longitudinal layer ; no cephalic grooves or lateral organs ; enteric 

 canal simple, and forming several coils ; nerve-trunks free from the 

 muscular system, and united posteriorly by an anal commissure ; a 

 broad sucker at the hinder end. 



Genus : Malacohdella. Characters of the family. 



Species : M. grossa O. F. M. Body flat and broad, mouth anterior, 

 pharynx broad ; transparent and white (male), or yellowish — grey- 

 green posteriorly — (female). Semi-pai'asitic in the mantle-cavity of 

 various Lamellibranchs. 



Geonemertes palcensis, Semper. — This interesting terrestrial Ne- 

 mertine, which was found by Professor Semper in the Pelew Islands, 

 has as yet been very incompletely observed. This animal, which is 

 from four to five centimetres long, is rounded and somewhat truncated 

 anteriorly, and of a reddish colour ; the head is provided with two 

 groups of eye-spots, of which there are three eyes in each, one larger 

 than the other two. The mouth is placed at the most anterior end 

 of the body ; the anus is dorsal, and the enteric tract is, as in most 



