134 



with a shining poUshefl surface ; it is filled with a gelatinous 

 slime and covered with minute puncture?. The polypo 

 orifices are large, distant, and of very irregular shape. Tlio 

 polypes, though seen, in consequence of other engagements 

 were not examined till they had become too much injured 

 for description. It varies in height to ten inches, and ia 

 thickness to six. This I have failed to identify with any 

 species described by the authors to whom I have access, and 

 in fact is now held to be new. 



A. ECHINATUM. Encrusting, thin; surface granular 

 when living, roughened with papillae when dead. 



A..echinatum, Fleming's Brit. An., p. 517. Johnston's 

 Brit. Zooph., p. 304, pi. 42., fig. 3, 4. 



Hab. On dead specimens of the Buccinnm vndatum, and 

 other dead univalve shells; coiuraon. Polperro, Mevagisaey, 

 Goran, and Whitsand bay. 



This species is invariably found encrusting dead univalve 

 shells, it is very thin, and of a brown colour. When living' 

 it is fleshy, slightly diaphanous;, and the mouths of the cells 

 are but slightly prouiinent ; when dry, it becomes hard, 

 phrivelled, and the apertures of the cells prominent and btifF, 

 The points or prickles, which are distributed over the 

 surface, have no permanent regularity, sometimes being 

 arranged in rows, as Dr. Johnston has figured them, and at 

 others distributed in a very irregular manner. 



Montagu first discovered it as a zooiih)te, on the Devon- 

 shire coast, and communicated it to Fleming; he says the 

 polypes have twelve tentacula. 



A. PARASITICUM. Parasitical on corallines, arenaceous; 

 cells difetant, round, or substance porous. 



A. parasiiicum, Fleming's Brit. An., p. 518. Johnston's 

 Brit. Zooph., p. 304, pi. 41, figs. 4, 5. 



Dr. Fleming first placed this among the zoophytes, but was 

 apparently undecided to what genus it belonged, not having 

 an opportunity of examining it in a living slate. It is found 

 encru!«ting the stems of the Scrlulariadce, as S. abietina, 

 and polyzottias. Plumvlaria Jalcata, ^c. In appearance it is 

 sandy, porous, and is about the tentli of an inch in thickness. 

 The cells externally, appear as minute distinct tubes, which 

 perforate the substance throughout. The polvpiclom, in fact, 

 instead of being secreted or formed by the animal as a part 

 of its own ciiaracter, as the polypidoms of all the others, is 

 formed of fine sand and mud, cemented together by a glairy 

 snbstHnce, as is observed in many worms, as in the Sabeilce, 

 Sfc.j' the whole appearance so closely approaches to what is 

 observed Id worms, that I atn inclined to think it the work of 



