18 TIIOCHOSMILID^E. 



circular wall arises from the floor and separates the iiiterse])tal 

 chambers in two, the onter portion becoming the rootiike ajipend- 

 age. The cavity of the roots opens freely into the interse])tal 

 chambers (Plate XIV., fig. 3), and is occupied by a fibrous extension of 

 the polyp. In old sj^ecimens the cavity becomes much reduced 

 by the thickening of the walls. 



The color of the polyp is greenish, or pale brick-red. 



This coral was obtained in about forty different casts along the 

 Florida reef, the least depth in which it was found being 49 fathoms, 

 the grciitest 324. The greatest abundance was between 100 and 

 200 fathoms. 



Height 2 to 2.8 cm., diameter of calicle 1.5 to 2 cm. 



TROCHOSMILID.E. 



rn,rl,o.<mil!(,cc(e M.-Edw. & H. 



For reasons elsewhere stated, f prefer to elevate this group to 

 the rank of a family, instead of leaving it among the Astra'iche as 

 a nu're section of the subfamily of Eiismilina'. the place assigned 

 to it by Milne-Edwards and llaime. Its attinities are jtartly 

 with the Astiu'ida^ and partly with the Turbinolidiv. We are not 

 sufficiently acipiainted with the value of the characters connecting 

 it with either to sa}' positively which of them ought to have the 

 ])reponderaiice. As a family, it appears homogeneous, but tiie 

 order or subordei' to which it ought to l)e altat-hed can be left 

 undetermined for the |)resent. 



The principal character by which to separate the Trochosinili(la> 

 from the Turbinolida' is the ])rcsenee in the foi-mer of dissepi- 

 ments closing the interseptal chaml)ers. In a large number of 

 them they are of a very rudimentary cliaracter, and no more de- 

 veloped than they are occasionally in true Carvo])hylIi;v% where I 

 have observed similar structures secreted abnormally to exclude 

 parasites. 



The mode of ])ropagati<)u ()l)served in three of tlie species here 

 described, namely, a gemmation from the interior of" the calicle, recalls 

 the peculiar intracalicinar gemmation of the Rugosa, and does not 

 prevail among an\- of the families of corals of the present epoch. 



