60 Lucerndria convolvulus, 



traction, and is altogether rather an active creature. It is 

 not so with L. convolvulus, which will remain for days on 

 one site ; and when detached by force from its hold, a pellicle 

 of skin is left on the spot, as if the connection had not been 

 broken without injury to its structure. Its motions are all 

 slow, and it is little susceptible of external impressions, so 

 that it will continue expanded until one is weary of watch- 

 ing ; and when it wills to contract, it does so lazily, and slowly 

 again resumes its former position. Such is the result of ob- 

 servations made on two individuals taken in Berwick Bay ; 

 and they correspond with those of my friend Dr. Coldstream, 

 who had previously taken this species on the shores of De- 

 vonshire. M I find," he says, " the animal very hardy. It 

 is constantly in a state of expansion, and does not contract 

 except when very rudely handled. One specimen has lived 

 with me for three weeks, although the water has not been 

 very often changed." 



Lucernaria convolvulus is about an inch in height, of a 

 uniform liver-brown colour, smooth, adhering by a circular 

 disk, above which there is a deep stricture; the disk even, 

 strengthened by an internal cartilaginous lamina, which rises 

 up the short peduncle, and forms a minute hollow firm centre. 

 The margin of the oral expansion is somewhat thickened, 

 and divided into eight equal arms, each furnished with a tuft 

 of numerous short tentacula tipped with a gland, and brighter 

 coloured than the body. The interior is hollowed like the 

 blossom of a flower, the square extensible mouth projecting 

 in the centre; and in the space between the arms there is a 

 complicated structure, composed apparently of a series of fo- 

 liaceous processes arranged on each side of a white line that 

 seems to spring from the sides of the mouth. These pro- 

 cesses, apparently branchial, are formed by the complicated 

 foldings of a thin membrane, attached by one side in the man- 

 ner of a mesentery : there are no vessels in the membrane ; 

 but some portions 6f it exhibit, when magnified, a kind of 

 network of irregular cells, and the outer free edge is bounded 

 by a thread-like line. The white central line which divides 

 them is formed of small roundish bodies, arranged in two or 

 three close series; and some of these ova can at times be 

 traced along the margin of the circumference to the tenta- 

 cula.* The latter are cylindrical, hollow, and terminated 



* " When I first procured it, the * two rows of spots ' running from 

 the mouth along each arm were prominent, and of a dark reddish-brown 

 colour. Sipce that time they have increased in size, and have become 

 studded with numerous white oval bodies, which I suppose to be ova. I 

 see some of these have made their way into the web connecting the arms, 

 but I have not observed any expelled from the body." {Dr. Coldstream.) 



