234 POTAMILLA EENIFORMIS. 



1893. Sabella reniformis, Lo Bianco. Atti Acad. Sc. Nap., 2 e ser., v, p. 67. 



1894. Potamilla „ Bidenkap. Christ. Vid.-selsk. Forhandl., p. 136. 



„ „ „ De St. Joseph. Ann. Sc. nat., 7 e ser., xvii, p. 292, pi. xi, figs. 296—298. 



1897. „ „ Michaelsen. Polych. deutsch. Meere., p. 182. 



1904. „ „ Journ. M. B. A., vol. vii, p. 231. 



1905. Pseudopotamilla reniformis, Bush. Tubic. Annel. Pacific, p. 203, pis. xxxiii, xxxiv and xxxvii. 



1906. Potamilla reniformis, De St. Joseph. Ann. Sc. nat., 9 e ser., t. iii, p. 241. 



1907. „ „ Soulier. Trav. Acad. Sc. Montpel., 2 e ser., t. iii, p. 121. 



1908. Pseudopotamilla reniformis, Moore. Proc. Acad. Nat. Sc. Philad., p. 359. 



„ Potamilla neglecta, Ehlers. Deutsch. Tiefsee Exped., p. 154, Taf. xxii, figs. 5 — 17. 



1909. „ reniformis, Fauvel. Bull. Inst. Oceanogr., cxlii, p. 42. 



,, ? „ neglecta, Moore. Proc. U.S. Nat. Mus., vol. xxxvii, p. 145. 



,, „ reniformis, Fauvel. Ann. Sc. nat., 9 C ser., t. x, p. 210. 



1910. „ „ Elwes. Journ. M. B. A., vol. ix, p. 65. 



1911. „ „ Fauvel. Bull. Inst. Oceanogr., cxciv, p. 37. 



,, „ „ Riddell. Proc. Liverp. Biol. Assoc, vol. xxv, p. 65. 



1914. „ „ Southern. Proc. Roy. Irish Acad., vol. xxxi, No. 47, p. 138. 

 „ „ „ Fauvel. Campag. Scient. Monaco, xlvi, p. 314. 



1915. •„ „ Allen. Journ. M. B. A., vol. x, p. 642. 



« „ „ Southern. Irish Sc. Invest., No. 3, p. 49. 



1916. „ „ Mcintosh. Ann. Nat. Hist., ser. 8, vol. xvi, p. 7. 



1917. „ „ Bioja. Anel. Poliq. Cantab., p. 63. 



Habitat. — Procured at extreme low water in fissures of rocks at Guernsey and Herm ; 

 also dredged in grooves in Pecten, and in tunnels in oysters ; in swarms in the Grouliot 

 Caves, Sark, where their tubes project from almost every chink, and occasionally they 

 are in groups, besides perforating the Balani on the floor and ledges. It spreads its tubes 

 through sponges and ascidians, bores the masses of Oellepora and various shells such as 

 limpets; tubes from Connemara (A. G. Moore) were crowded with the tubes of a sessile- 

 eyed crustacean. Plymouth (Allen) ; Torquay (Ehlers) ; West Coast of Ireland, 

 Blacksod Bay, etc. (Southern). 



Distribution. — The distribution of this form is wide, viz. from the Arctic Seas to the 

 Mediterranean; Norway (Sars); Behring's Sea (Marenzeller) ; Finmark (Norman); Iceland 

 (Leuckart) ; Greenland and Finmark (Malmgren) ; shores of Cantabria (Rioja) ; St. 

 Lawrence, Canada (W. C. M.) ; Atlantic Coast, North America (Leidy and Verrill). 



North Pacific Coast of North America (Moore) ; shores of France (De Quatrefages, 

 De St. Joseph, Fauvel) ; Mediterranean and Adriatic (Grube, Panceri, Marion and 

 Bobretzky) ; Madeira and Teneriffe (Langerhans, Fauvel) ; Naples at considerable depth 

 (Lo Bianco). 



The cephalic plate, when the branchiaa are shed, presents dorsally a bilobed collar or 

 lamella, the deep dorsal furrow terminating in the centre. The outer edge of each flap 

 is continued as a broad rim nearly to the mid-ventral line, where a notch separates the 

 two sides, which curve forward. The truncated surface has a projecting transverse 

 fold at the upper end of the ventral incurvation, and two folds meet above it so as 

 to make a triradiate aperture. 



The branchias are about ten or eleven (twelve to fifteen, De St. Joseph, Leuckart) 



