26 Dr. E. P. Wright on a new Genus of Gorgonidse. 



subfamily Isidinse ; but if we refer to one of the latest works 

 on the structure of the Ccelenterata, that of Kolliker*, we find 

 an arrangement of the Gorgonidaj which, while essentially 

 based on that of Milne-Edwards, departs in several particulars 

 from it. Instead of three subfamilies, Kolliker establishes six, 

 (1) Gorgonina?, (2) Isidinae, (3) Briareaceas, (4) Sclerogor- 

 giacea?, (5) Melitheeacese, (6) Corallinae ; and, passing over 

 the characters given for the other subfamilies, we find the 

 second and fifth characterized as follows : — 



(2) Isidince. — Axis jointed, composed of horny and calca- 

 reous portions ; of these the latter possesses a lamellose struc- 

 ture, and maintains its form after it has been placed in alkali. 

 Genus Isis. 



(5) Melithceacece. — Axis jointed ; the flexible (soft) joints 

 consisting of calcareous spicules surrounded by horny sub- 

 stance and connective tissue, the hard joints of coalesced cal- 

 careous spicules. Genera Melithcea and Mopsea. 



It is interesting to see that this classification of Kolliker's, 

 though it is based on the minute structure of the polypes and 

 their coenenchyma, does not differ very essentially from those 

 already proposed by others, though they are based on more 

 general considerations ; but I am at a loss for a reason why 

 these two subfamilies, which certainly are very nearly allied 

 to one another, should be so far separated as in this scheme, 

 the more especially as there are several species of Mopsea 

 which are very closely related indeed to some species of Isis ; 

 and we may expect to find in Dr. Gray's Catalogue very 

 many species intermediate between those at present known. 

 But regarding for the moment the family Isidas as having but 

 the one genus Isis, and the typical species of this genus to be 

 the/, hippuris (Linn.), then lam inclined to regard Keratoisis 

 Grayii as having the same relation to it that Mopsea arbus- 

 cidum, Yate Johnson, has to the genus Mopsea : for this latter 

 species Dr. J. E. Gray proposes the new genus Acanella ; so 

 that these genera may be arranged thus : — 



Subfamily Isidinre, with the genera Isis and Keratoisis. 



„ Mopseadiiue, with the genera Mopsea and Acanella. 

 I trust to have soon an opportunity of examining the spicules 

 of several species of the latter two genera, as well as of several 

 species of Isis, and may probably, in a paper describing some 

 Alcyonaria from Australia, give a more detailed account of 

 their histology. Kolliker figures, in tab. 19. figs. 1-3 of his 

 ' Icones,' very beautifully and very truthfully the spicules of Isis 

 hippuris, and those of Mopsea in figs. 41-44 of the same plate. 

 * Icones Histiologies, Part 2, 1866, p. 131. 



