ANTHOZOA HELIAXTHOIDA. 185 



of this opinion. It appears in fact that they are male organs 

 for the secretion of the seminal fluids, Professor Wagner hav- 

 ing discovered spermatic animalcules in them.* They are 

 undoubtedly tubular, although Mr. Teale acknowledges that 

 he has not been able to obtain any evidence of the fact, and 

 " under the microscope it appears simply as a round, solid, 

 translucent chord." Such also has it always appeared to me, 

 so that I can scarcely hesitate to pronounce Dicquemare's de- 

 scription of its structure to be incorrect. " I have observed," 

 he says, " that there grows or comes out of their body and 

 mouth a sort of threads about the size of a horse-hair, which, 

 being examined with a solar microscope of five inches dia- 

 meter, appear as if made up of a prodigious number of vessels, 

 wherein a liquor is seen to circulate. The largest of these 

 unite together, much in the same manner as the optic nerves 

 do in man. "{ 



The external envelope of the naked Hydro'ida is a thick firm 

 fleshy or coriaceous skin consisting of a corium and epidermis, 

 the former layer constituting the chief organ of support, 

 and giving to the animal its peculiar form. " A circular hori- 

 zontal portion forms the base or foot ; a cylindrical vertical 

 portion constitutes the sides, and is inflected at the superior 

 border, so as to form a thick rounded lip. The corium is 

 afterwards prolonged over the tentacula, giving investment 

 and form to these organs, and is then extended horizontally 

 to form the roof, near the centre of which it again becomes 

 folded upon itself, forming an internal lip or mouth, at which 

 part it is continuous with the digestive sac."| " The epider- 

 mis forms a thin layer of unorganized matter spread over the 

 whole extent of the corium, and may be traced into the 

 stomach. The external surface of the epidermis is dense and 

 membranous ; internally, when examined by the lens, it ap- 



contained certain bulbs, or buds, " which open in time, and cleaving to the bodies 

 on which these threads are extended, produce small anemonies." Phil. Trans, 

 abridg. xiii. 639. 



* Ann. des Sc. Nat. viii. 283. Professor Owen attributes to them the same func- 

 tion, Lect. p. 87 ; and The Lancet, No. 871, p. 225. I know not how to reconcile 

 the fact with some statements in the volume of " Reports" published by the Ray 

 Society, p. 381 (1845). Erdl is convinced that the sexes are separate. 



t Phil. Trans, abridg. xiii. 639. j Teale in lib. supra cit. 93. 



