AMMOTRYPANE. 217 



description. It is difficult to decide which is the anterior, and which 

 the anal extremity. I have been guided in my determination by the 

 direction of the cirri, which I presume point backwards, and by the 

 fact that I found the intestine near what I have called the tail, filled 

 with a fine quartzose sand, while it was empty at the opposite end. 

 By its form and rigidity it reminds one of the Amjphioxus ; and the 

 distinct manner in which the dorsal is separated from the ventral 

 disk, with the structure of the latter, calls up a comparison with a 

 narrow Limax. 



There is in some specimens a black speck on each side behind the 

 snout, but it is uncertain whether these are eyes. 



Rathke's figure exactly represents our specimens ; and his descrip- 

 tion is probably superior to ours, from having been derived from living 

 specimens. Unfortunately we have not been able to benefit from it. 



(a) CuUercoats, Northumberland, Jos. Alder. 



(b) CuUercoats, Jos. Alder : and Firth of Forth, Lieut. Thomas, 

 R.N. 



31. AMMOTRYPANE. 



Ammotrypane, RathJce in Nov. Act. Acad. Nat. Cur. 1843, xx. 188. 

 Gruhe, Farm. Annel. 70. 



Char. Head continuous with the body, produced to a point : seg- 

 ments more or less ringed, the dorsal surface rounded, the ventral 

 flat, but the limaciform sole abbreviated in front : braachise cirri- 

 form, in a single series on each side, connected with the feet of the 

 posterior portion only : feet slightly protuberant, with two fan- 

 shaped tufts of bristles : anus with a circle of small papillae. 



1 . A. limacina. 



Ammotrypane limacina, Rathke in lib. cit. 190. tab. 10. f. 4-8. Grube, 



Fam. Annel. 70. 

 Ophelia eruciformis, Johnston, MSS. 



Hab. Near low- water. 



Desc. Worm 1^2", thick proportionably, grub-like, smooth, very 

 convex dorsally, with a thickened indented line along each side on 

 which the feet are placed ; the ventral surface flat, formed like the 

 muscular foot of a gasteropod. The whole body is encircled with 

 narrow slightly raised lines, which are most conspicuous on the 

 anterior third, and less perceptible on the middle and posterior por- 

 tions. The anterior portion consists of seven segments composed of 

 three or four rings, and is distinguished by being conoidal, with less 

 developed abranchial feet, and no ventral furrow. It is fully one- 

 fourth the length of the entire body, becomes snout-like in front, 

 and is terminated with a mucro. There is a short furrow on each 

 side. Mouth large, inferior, transverse, with a thick lip ; and a 

 groove on each side bounds the soles of the whole anterior portion. 



