Zoological Society, 299 



Holothuridse, the great distinction between them being that in the 

 Holothuridae the pupa has already passed through the more active 

 "Auricularian " stage, while the analogous form in Comatula has 

 been developed directly from the egg. 



ZOOLOGICAL SOCIETY. 



Nov. 11, 1862.— Prof. Huxley, F.R.S., V.P., in the Chair. 

 Descriptions of Two Corals from Madeira, belonging to 



THE GENERA PRIMNOA AND MoPSEA. By JAMES YaTE 



Johnson, Corr. Mem. Z.S. 



Fam. GORGONIIDiE, M.-Edw. 



Subfam. Gorgoniin^e, M.-Edw. 



Sect. Primnoace^e, M.-Edw. 



Primnoa imbricata, sp. n. 



White, having a tendency to branch dichotomously in one plane ; 

 the branches slender, flexible, not plume-like, and not anastomosing. 

 Axis pale brownish yellow, spineless, obscurely striated, effervescing 

 in hydrochloric acid, coated with small white scales composed of 

 carbonate of lime. Over the lower coating of scales there is another 

 coating of larger scales, with a wide space between the two. The 

 outer coat, which is easily removed, appears to be attached to the 

 peduncles of the cells. These peduncles are in closely-set whorls of 

 three or four, each of which expands into a cup-like cell, having its 

 mouth closed in the dead coral with eight scales that have their 

 apices in contact. The peduncles project at right angles from the 

 stem, and are also clothed with scales. 



This is a much more delicate form than Primnoa lepadifera, in 

 which species the pedunculated cells appear to be arranged spirally 

 on the branch. 



Two specimens of this elegant Primnoa have been obtained, the 

 larger of which has a height of 8^ inches, with a width of 1 1 inches. 

 It was attached to a piece of Lophohelia (Oculina) prolifera. The 

 whorls of the pedunculated cells are about three-twentieths of an 

 inch apart, and the peduncles about the same in height. The prin- 

 cipal branch, near the base, has a diameter of one-fifth of an inch. 

 The smaller example has been deposited in the British Museum. 



Subfam. Isidinje, M.-Edw. 



MOPSEA ARBUSCULUM, Sp. n. 



The whole coral is coated with a thin brown skin. When this 

 skin has been removed from the lower calcareous joints, they are 

 found to be stony, white, subcylindrical, but rather narrower at the 

 middle than at either end. They are finely striate longitudinally, 

 and the striae are parallel and straight. The interjoints do not 

 nearly equal the joints in length, being little more than discs, and 

 are somewhat less in diameter. They are striate, and from them 

 spring the branches. These branches are very numerous, diverging 



20* 



