No. 1.] ACTINIARIA OF THE BAHAMAS. 61 
ing forms. He recognizes two families in the tribe Zoanthez, 
the Zoanthidze and the Sphenopidz. Andres’ classification 
(83) is not so advanced as that of Hertwig, since he makes 
the family Zoanthinze equivalent to the sub-tribes of the Hex- 
actiniz as here recognized. 
I would recommend an arrangement combining those of 
Hertwig and Andres. I would recognize Hertwig’s tribe 
Zoantheze and its equivalency to the Cerianthez, etc., and 
assign to it the three families given by Andres, viz.: the 
Zoanthidz, the Bergidz, and the Sphenopidz. 
Genus ZOANTHUS (Cuv.), Erdmann. 
Zoanthidz with fleshy walls, there being no sand or foreign 
matter imbedded in the mesogloea; the coenenchyma is stolon- 
like, with a slight tendency to form plate-like expansions. The 
mesenteries are arranged on the microtypus, and the sphincter 
muscle is imbedded in the mesogloea and is double. 
The synonymy of this genus, as indeed that of all the genera 
of the Zoanthidze, is very much confused, and instead of giving 
it in full, I have thought it better to present in a concise form 
the limitations of the genus as given by the principal author- 
ities. 
I. Actinians united in considerable numbers on a common 
base — Cuvier (’17), Gosse (60). 
II. Actinians with the individuals united by stolon-like pro- 
longations — Lesueur (17), Ehrenberg (34), Dana ('46), Milne- 
Edwards (57), Duchassaing and Michelotti (60), Gray (67), 
Verrill (68), Hertwig (82). 
III. Colonial actinians with fleshy walls — Klunzinger ('77), 
Andres (’83). 
IV. As defined above — Erdmann (85). 
The arrangement of the mesenteries in Zoanthus was first ac- 
curately made out by R. Hertwig (83), and his results were later 
confirmed by G. Miiller (84), Erdmann (85), and W. Koch ('86). 
Erdmann, however, first made this arrangement, taken in con- 
nection with the nature of the sphincter, of generic importance, 
separating forms in which, like Zoanthus, the second pair of 
mesenteries in each side, counting from the micro-directives, 
consists of a macro- and a micro-septum, from those in which the 
