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

 slime and covered with minute punctures. The polype 

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

 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 in 

 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. 



Bab. On dead specimens of the Buccinum undatum, and 

 other dead univalve shells; common. Polperro, Mevagissey, 

 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 prominent; when dry, it becomes hard, 

 shrivelled, and the apertures of the cells prominent and stiff. 

 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 zoophyte, on the Devon- 

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

 polypes have twelve teutacula. 



A. PARASITICUS!. Parasitical on corallines, arenaceous; 

 cells distant, round, or substance porous. 



A. parasiticum, 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 state. It is found 

 encrusting the stems of the Sertutariadce, as <S'. abielina, 

 and polyzonias, Plumularia Jalcata, $c. In appearance it is 

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

 The cells externally, appear as minute distinct tubes, which 

 perforate the substance throughout. The polypidom, in fact, 

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

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

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

 substance, as is observed in many worms, as in the Sabella, 

 §c. j the whole appearance so closely approaches to what is 

 observed in worms, that I am inclined to think it the work of 



