M^A. 2/9 



believes, while digging with the trowel for littoral mollusca ; and we 

 may conclude, from its structure, that it is arenicolous, probably the 

 tenant of a thin and fragile tube. How it disposes its oral filaments, 

 when in its natural condition, it is hard to say. That they are 

 branchial scarcely admits of a doubt, notwithstanding their anoma- 

 lous position. When highly magnified, the rachis is seen to be per- 

 meated by a comparatively large canal running from the base to the 

 summit, — undoubtedly an aquiferous canal ; and every cirrus of the 

 myriad that fringe and adorn the upper aspect is a cylindrical obtuse 

 organ, containing a sort of dark grumous or granular texture within 

 a thick transparent coat or skin, — a texture produced by decay and 

 steeping in spirits, but very like the branchial texture in other 

 genera of the class. 



It is difficult to assign a place to this worm in our present classi- 

 fications. The head leads us to compare it with some Nemertince, 

 for example with Ophiocephalus ; and yet there is no relationship 

 there. With the Terricoles there is much accordance in the general 

 habit, and in the structure of the abdominal portion, more especially 

 in the feet of the bristles being in four fascicles ; and there are Naides 

 in which the head is distinctly marked as in this new genus, and in 

 which there are two, kinds of bristles. Yet it is doubtful whether 

 the resemblance is not merely analogical. To refer the worm to the 

 AriciadiE is a kind of compulsory connexion, for that family is 

 becoming a refuge of unclaimed foundlings. All the Ariciadce 

 known have the branchiae placed dorsad on the feet, and inti- 

 mately combined with them ; but in this worm they are cephalous, 

 and are far removed from the feet, which are only developed in a 

 small degree. Then for the Tubicolce there are even less claims. 

 The distinct head without appendages, the want of hooklets on the 

 segments*, the quadriserial fascicles of bristles, and the position of 

 the mouth, are all proofs against any true relationship. It may, 

 however, be noticed here, that were the branchiae of Pectinaria to be 

 drawn out into a line, we should have an organ something like to the 



branchial filament of ? In these doubts, there really seems no 



alternative but to make this genus the representative of a distinct 

 family. 



* These may be represented by the hard granules, but the latter have no regu- 

 lar position nor form. 



