364 PENNARIA CAVOLIXII. 



PERiSARC. IlrDRAXTns flask-sliaped, with the filiform tentacles constituting a proximal 

 set, and arranged in a single verticil round the base of tlic hydranth, and the capitate 

 tentacles a distal set scattered on the body of the hydranth. 



GONOSOME. — GoNOPHORES developed in a more or less perfect verticil between 

 the proximal and distal sets of tentacles. Umbrella deeply ovate ; manubrium large, 

 destitute of oral appendages ; marginal tentacles four, rudimental, no ocelli. 



The genus Pennuria was constituted by Goldfuss for the Scrfiihiria j)e»iiaria of Cavolini, a 

 well-marked generic form, so well marked as to justify its assumption as the type of a distinct 

 family of Gymnoblastic hydroids. 



*:j^* 1. Pexnaeia Cavolinii, EJirenhcrg. 

 Woodcut, fig. 80. 



Serti'laria PENNARIA, — CavoUni, Mem. Pol. Mar., Sprengel's trans., p. 61, tab. v. 

 Pennaria disticha, — Goldfuss, Handbuch der Zool., p. 89. 



Pennaeia Cavolinii, — E/irenberff, Corallenthiere, Abhandl. Akad. Berlin, 1832, p. 297. 



K'6lliker, Zeitschr. f. Wiss. Zool., vol. iv, 1853, p. 303. 



TROPHOSOME. — ^IIyduophxton attaining a height of six or seven inches ; main 

 stem slightly zig-zag, and with a uniform and gentle curve from base to apex ; 

 branches given off alternately from each side, with a regular distichous arrangement, 

 PERISARC annulated at the origin of the branches, and on the ultimate hydranth- 

 bearing ramuli. IIxdrantus borne on the summits of the main stem and primary 

 branches, and on those of very short simple nearly cylindrical ramuli, which spring at 

 regular intervals from the distal side of the primary branches; body of hydranth 

 tumid at the base, and thence rapidly tapering to the mouth, so as to assume the form 

 of a flask ; filiform tentacles about twelve, terminating in blunt, slightly swollen 

 extremities, and springing from a zone at some distance above the base of the hydranth ; 

 capitate tentacles about twenty, much shorter than the filiform. 



GONOSOME. — MEDUSiE long ovate, borne on short peduncles, and springing from 

 the body of the hydranth just within the base of the verticil of filiform tentacles ; 

 marginal tentacles in the form of four small tubercles. 



Coluiir of liyclrocaulus brown, becoming paler at the apices of the branches ; thick basal 



