a new species Jrom the Arctic Seas. '"' 151 



second pair of antennae, there are two rudimentary lips embrac- 

 ing the proboscis. Near the back part of the lower surface of 

 the head arise two fleshy peduncles (m) from the same broad 

 fleshy protuberance, and extend forward along the base of the 

 head. Each of the fleshy peduncles is terminated anteriorly by 

 a broad compressed white horny hook, (I) curved inwards, and 

 tuberculated on its concave margin like the pincers and the in- 

 ner jaws of a crab. The hooks are strong, white, opaque, 

 and elastic ; and the outer covering of the whole head is of an 

 elastic horny texture, so transparent on the upper surface as 

 to allow the internal parts to be seen through it. On remov- 

 ing this horny case from the head, a very complicated, though 

 extremely minute structure presented itself beneath. Within 

 the anterior prominent beak there was a white pulpy matter 

 like the ganglion we find in that situation in crabs, and the 

 nerves of the tentacula could be traced nearly to that part. 

 There was no appearance of eyes on this remarkably distinct 

 head. The head is united to the body by a very narrow 

 contracted neck, (d) as in insects. The bodi^ is of a lengthened, 

 straight, and subconical form, slightly carinated longitudinally 

 in the middle of the anterior and posterior surfaces, prominent 

 and muscular along the sides, and marked transversely with 

 two small contractions in the upper narrow part, and one near 

 the middle. The membrane covering the body is so trans- 

 parent before and behind, as to exhibit the glandular parts 

 surrounding the intestinal canal within. The body is a little 

 ventricose in the middle, and terminates suddenly below by a 

 broad and lobed base, in the middle of which two large pro- 

 minent labia conceal the anus, (e.) The intestinal canal, of great 

 width, passes in a straight line from the mouth to the anus 

 without the slightest convolution or curvature. The upper 

 part of the intestinal canal in the situation of the neck (imme- 

 diately below d) I found much dilated, of a glandular texture, 

 and filled with a firm yellow coagulated matter, probably the 

 remains of the food last swallowed. I have found a similar 

 coagulated matter, of a darker colour, filling the intestinal canal 

 of the skate-leech, ( Pontohdella muricata^ Lam.) which lives 

 by sucking the white blood from the surface of the skate. 

 The whole digestive canal of the L. ehngata was surrounded 



