101 



This species on our coast attains about three inches in 

 height, but is more commonly found about one. It is of a 

 light brown colour, and though much and diohotomously 

 branched, is not spreading, growing much like a poplar tree; 

 the branches are slender and formed only of the cells, which 

 are united in pairs, with a joint between each pair. Tim 

 cells are opposite, united at their backs, smooth and obliquely 

 truncated. The appearance of the cells thus united is aptly 

 said by Ellis, " to resemble a coat of mail or pair of stays; 

 and the entrances of the cells look like the places for the 

 arms to come out at." The polypes have ten ciliated 

 tentacula, and are very active. 



HIFPOTHOA. Lamouroux. 

 Generic Character: Polypidoms confervoid, adherent and 

 creeping, calcareous, irregularly branched, the branches 

 frequently anastomosing, formed of eliptical cells linked 

 to each other at the extremities ; aperture lateral, near 

 the distal end. Polypes ascidian. 



BEADED CORALLINE. //. Catenularia. Cells egg- 

 shaped, smallest end towards the centre of growth; aper- 

 ture large, oval, and at the larger end. PI. xviii., fig. 5. 



Hippothoa catenularia, Fleming's Brit. An., p. 534. John- 

 ston's Brit, Zooph., p. 264, pi. 31, figs. 9 and 10. 



Hab. On the Pinna ingens and P. rotundata, very com- 

 mon. Polperro; Deadman point. 



This is to be found on almost every Pinna drawn from deep 

 water off the Deadman point, and west to the Lizard. It is 

 a small bead-like coral, running over the surface of the shell. 

 It is adherent throughout, and formed of egg-shaped cells 

 linked together at their extremities. The larger end, placed 

 distally, is occupied by the aperture, which is oval, and 

 sometimes very large with a plain thickened rim. As it 

 trails over the surface of the shell it is much and variously 

 ramified. The ramifications arise at nearly right angles 

 from the margins of the cells opposite the lower margin of 

 the orifice, and frequently cover two or three inches of 

 surface. Sometimes the cells are so thickly arranged as to 

 be placed in juxtaposition over half an inch of surface, in 

 such a case it very closely resembles a Flustra; and on three 

 occasions it was only by examining the free cells of the 

 circumference that the character of the polypidom was de- 

 termined. When thus jointed into a Flustra-like form, the 

 cells appear inflated, and the apertures immersed ; some- 

 times the surface is smooth and the situation of the cells only 

 marked by the rounded apertures. In its more usual form 

 it is variously ramified and resembles, as Dr. Johnston has 



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