45* 



SIMILITUDE TO CORALS. 



more than a rapid mention of the names of the next few engravings, together with a 

 brief account of one or two of the more interesting examples. 



IN the group of polyzoa given in the accom- 

 panying illustration, the reader will not fail to 

 notice the great external similarity between their 

 forms and those of the true stony corals so 

 familiar to us. It will, moreover, be found, that 

 in many details of their structure, there is a 

 decided analogy between them and the true 

 zoophytes which will be described in the latter 

 part of the work. 



Fig. A, Plate V., represents the Crisia eburna 

 of the natural size, and just below, at fig. B, is 

 given a portion of the same species as it appears 

 when magnified. The arrangement of the cells is 

 simple and elegant, and the various branches are 

 connected with each other by means of certain 

 horny joints. The use of these joints is, in all 

 probability, to enable the polyzoary to resist the 

 action of the waves, and so to avoid the fractures 

 which would probably result if the joints were as 

 stiff and inflexible as the cells. A similar pro- 

 vision will be seen in the Gorgonia, a zoophyte 

 which will be described on a future page. 



A remarkably constructed species, the Idmonea 

 atlantica, is shown at fig. C, where it may 

 be seen looking something like a many-legged 

 spider, with its branches protruding from a 

 rounded centre which represents the body of 

 that animal. Two magnified representations 

 of this curious species are to be seen at figs. D 

 and E, the former giving the front view and the 

 latter the lateral aspect, in order to show the 

 peculiar construction of the polyzoary, and the 

 firm manner in which the cells are set upon 

 their common basis. For the figures in this 

 and several of those of the succeeding plates, I 

 am indebted to the kindness of Mr. Bush, who 

 allowed them to be taken from his forthcoming 

 part of the " Catalogue of Marine Polyzoa." 



At fig. F is seen a small portion of a polyzoon 

 termed Pustulopora delicatnla, the generic name 

 being on account of the minute dots with which 

 the surface of the cells and polyzoary is studded, 

 and the specific title in reference to the delicate 

 structure and soft brown hue with which it is 

 colored. The same specimen is represented at 



POLYZOA V. 



A. Crisia eburna. B. Crisia eburna. X 



C. Idm6nea atlantica. 

 D. Idm6nea atlantiea. X (Front view.) 

 E. Idm6nea atlantica. X (Side view.) 



F. Pustul6pora delicdtula. 



G. Pustuldpora delicatula. X H. H(5rnera. 



The sign X signifles that the object is 



magnified. 



fig. G, much magnified, and is remarkable for the 

 profusion and great comparative length of the cells. The last figure in the engraving, 

 marked H, is a stoutly-built polyzoon named Hornera, and is notable for its resem- 

 blance to several corals. 



IN the species given in Plate VI. the resemblance to the corals, the madrepores, 

 and even the stony habitations of certain marine worms, is very close and striking. 



Fig. A represents a polyzoon fancifully entitled Alecto, in honor of one of the Furies 

 of that name. It is seen of its natural size as it appears while spreading itself over the 



