108 E.ev. T. Hincks on Polyzoa 



peculiar; it is developed at some distance above the mouth, and 

 is apparently quite separated from it at first, though at a later 

 stage united to it by an extension of the peristome, as Smitt 

 has remarked. Judging from Busk's figure, I should also 

 suppose that the avicularia differed in character in the two, 

 though this portion of the structure is badly preserved in the 

 fossil. 



In R. WalUcMana there is none of the remarkable thickening 

 of the branches behind, nor is there any trace of the "crescen- 

 tic laminee " which are ascribed to the other species. Its 

 dorsal surface is flattened, traversed by raised lines, which for 

 iho, most part run longitudinally, while that of R. notojpachys 

 is marked by deep, usually transverse sutures. The fenestrge 

 also seem to be much smaller in the latter form. 



In the present species the zoooecia are sometimes very indi- 

 stinct, at others they are well defined by conspicuous raised lines. 

 On the dorsal surface, at the base of each fenestra there is an 

 immersed avicularium, placed transversely, 



Iceland, 100 fathoms, apparently common. 



[Spitzbergen, 20-80 fathoms, common ; Finmark [Smitt) ; 

 Godhaab, 150 fathoms [Busk).'] 



Suborder Cyclostomata. 

 Genus Grisia, Lamx. 



26. 'Crista denticulata^ Lamk. 



Iceland, 100 fathoms ; several small fragments occur. 

 [Norway [Sars] ; Spitzbergen ; Bahusia (teste Smi(t) ; 

 Great Britain &c., Scotch Glacial deposits (Geikie).] 



Genus Idmonea, Lamx. 

 27. Idmonea atlantica, E. Forbes. 



Iceland, 100 fathoms ; abundant. 



[Scandinavia, from Bahusia to Finmark, common (Sars, 

 Lovet}, Smitt)', Shetland (Barlee) ; entrance of Baffin's Bay, 

 175 fathoms {N'orman).'] 



Genus TuBULiPORA, Lamk. 

 28. Tubulipora ventricosa, Busk. 



Iceland ; on SertulareUa tricuspidata, Alder. 

 [West Greenland, on Fucus [Sutherland).'] 



