Hicksonella, a New Gorgonellid Genus. By J. J. Simpson. 687 



was first described and figured by Kolliker in his Icones Histio- 

 logies, p. 140, taf. xviii. fig. 46. In the Ee vision of the Juncellid- 

 group of the Gorgonellidse several figures of this type of spicules are 

 given (fig. 4, a-g). 



The general form approaches that of the well-known " Indian 

 club ;" there is a distinct smooth median part or handle, which is 

 surmounted by a few spines. The club-part also bears spines, and 

 the most important characteristic is the fact that these species are 

 all directed away from the shaft, and do not arise perpendicularly. 



Some doubt seems to have arisen since the time of Kolliker as 

 to the exact nature of the " club," and this dubiety accounts for 

 the original inclusion of the species spiralis in the genus Juncella. 

 Hickson (op. cit.) describes a form of spicules as a club (pi. viii. 

 fig. 8), but it is a club essentially different from Kolliker' s type. 



The spiculation as a whole is quite unlike that of any species of 

 Juncella (op. cit., figs. 14, 23, and 26), so that it is impossible to 

 refer the present specimens to that genus. They are even further 

 removed from Scirpearia and Nicella, so that it seems necessary to 

 form a new genus to include them. 



o v 



Diagnosis of Hicksonella g. n. 



Colony simple, flagelliform, and generally twisted in a more or 

 less open spiral at least in the older colonies. The axis consists of 

 concentric lamina; which are composed of a horny substance im- 

 pregnated with some form of calcareous matter. It is generally 

 hard, and the surface is marked by longitudinal ridges and furrows. 



The ccenenchyma is extremely thin and densely spiculose ; it 

 is very brittle, especially when dry. The polyps are disposed iu a 

 broad longitudinal band ; this leaves a narrow bare strip which 

 traverses the whole length of the colony. The verrucas are not 

 retractile into the ccenenchyma, and are elongated, slender and 

 slightly club-shaped in the upper portion ; they are covered with 

 minute spicules, which appear like overlapping scales ; the spicules 

 on the aboral surface of the tentacles form a sort of pseudo- 

 operculum to the partially retracted anthocodia. 



The spicules vary in the different species, but the following 

 are the chief types : — (1) Irregularly warted spindles ; (2) flat, 

 smooth, or slightly warty scales ; (3) large irregular forms ; (4) 

 crosses ; and (5) bi-rotate forms. 



Specific Diagnoses. 



Hicksonella spiralis (Hickson) = Juncella spiralis Hickson. 



Colony unbranched ; in the larger forms spirally twisted. The 

 ccenenchyma is thin and densely packed with scale-like spicules ; 

 the axis is composed of concentric lamina? of a horny substance, 



