VARIOUS DOLYZOA. 



449 



the membrane of the upper part of the cell, from which, the semicircular edge aud lip can 

 recede if pushed from within. 



Suppose, yet again, that in every cradle there lies a baby with its little knees bent up 

 to its chin, in that zigzag posture that children, little and big, often like to be in. But 

 stay, here is a child moving ! Softly and slowly pushes open the semicircular slit in the 

 coverlid, and we see him gradually protruding his head and shoulders in an erect position, 

 strengthening his knees at the same time. He is raised half out of bed, when lo ! his 

 head 'falls open, and becomes a bell of tentacles. The baby is the tenant polype." 



.Fio-. C is the Toothed Sea Mat, given in order to show the curious toothlike appendages 

 trom which it derives its name. 



POLY/UA, III. 



A. Fiiustra foliacea. (Sea Mat.) 



B. Flustra foliacea. x 



C. Fliistra denticulata. x (Toothed Sea Mat.) 



D. Carbasea episcopdlis. x (Bishop's Mitre.) 

 G. Didchoris magelldnicus. x H. Membranipora 



E. Carbasea episcopdlis. 



I. Membranipora pildsa. x 



F. Didchoris crotali. x 

 K. Leprdlia Landsborovii. 



L. Leprdlia spinifera. 



M. Leprdlia spinifera. (Ovicell. x) 

 The sign x signifies that the object is magnified. 



N. Leprdlia trispindsa. 



At E is seen a curious polyzoou, found in Bass's Straits at a depth of forty-five fathoms, 

 and bearing the name of Carbasea episcopalis. This species is found in two forms, either 

 parasitic on sertularia and various polyzoa, and then of small size, or leading an 

 independent existence, and reaching considerable dimensions. It is chiefly remarkable 

 for the singular form of the ovicells, which bear a wonderfully close resemblance to 

 bishops' mitres, and have earned for the species the title of episcopalis. A group of these 

 ovicells may be seen at fig. D. 



Two specimens of another genus may be seen at figs. F and G, the former representing 

 a single cell of Diachoris crotali, for the purpose of showing the remarkable appendages 

 which guard the mouth ; and the latter, Diachoris Magellanicus, exhibiting the method 

 iff which each cell, except at the margins of the fronds, is connected with six others, 

 something like the stellate cells in pith. In fact, the Diachoris is a flustrum dissected, 

 the cells being drawn away fiom each other and connected by stalks. In the illustration, 

 the connecting stalks are well shown, by which the central cell is united to the six that 

 surround it, and several of the avicularia are also given. 



Any one who picks up a piece of a dark seaweed, will find that many parts of its 

 structure are covered with a peculiar growth, that looks as if a portion of Sea Mat had 



3. G G 



