278 HYDROID^. Part IV. 



consists of a spongy mass of very large cells, whose interstices are permeated, in 

 every direction, by jjrolongations from the peripheric longitudinal tubules. The 

 universal permeation of these irregular interstitial chymiferous lacunte, among the 

 enormous cells of the core, at once explains the great distensibility and contrac- 

 tility of the stem. 



The medusoid. — The medusie-buds of this Hydroid do not become free individuals, 

 but, remaining attached, develop their generative material, and then wither and die. 

 The form of the bunches of medusas, and their manner of attachment to the base 

 of the proboscis of the hydroid, is the same as in Tubularia (PI. XXIV.) ; and 

 the mode of development of the walls of the disk and proboscis, and of the 

 radiating and circular tubes, is also the same as in that genus. The figures of 

 the early stages of the medusoid of Tubularia, on PI. XXIV., can hardly be distin- 

 guished, either in form or color, from those of our Corymorpha, and if we were 

 to elongate one of the four corners of PI. XXIV. Fig. 13, which represents the 

 male medusa of our Tubularia, into a thick tentacle, about half as long as the 

 disk, and place, on the outer surface of the bell, over each radiating tube, a narrow 

 longitudinal band of enormously developed cells, Ave should have a medusa of 

 Corymorpha pendula. The proboscis, in our specimens, which are males, is capped 

 by an enormous, dusky j^ellow, spermatic mass, which completely fills the disk, and 

 at times projects through the aperture to a considerable extent. When fully 

 ripe, the spermatic mass has a dead white color, and the medusa is only a little 

 more pointed than that of Tubularia, as represented in PI. XXIV. Fig. 5. 



SECTION VII. 



THE PENNARIDvE. 



Pennaria gibbosa Ag. — Though generally referred to the family of Tubularidae, 

 the genus Pennaria constitutes a distinct family,^ to which a few other recently 



* References to the Pennaridae. Pennaria, Kolliker, Zeitschrift fur Naturwissenschaft, 



Pennaria, Goldfuss, 1820, Handbuch der Zoologie, 1853, Vol. IV. p. 303. 



p. 89. (Pennaria, Oken, 1815.=Ania- " McCrady, Proc. Elliot Soc, Charleston, 

 thia, Lamx., 1812. =: Serialaria, Lamk., S. C, 1858, p. 50. 



1816, a Bryozoon.) " Sars, Nyt. Mag., 185G, p. 156. 



" Milne-Edwards, in Lamk. An. Sans Vert., " Ehrenberg, Corall. Konigl. Akad. Wiss., 

 2d ed., 1836, Vol. II. p. 161, note. Berlin, 1834. 



