48 PRIMNOAD.E. 



151. Thesea exserta. 



Coral branched ; terminal branches very slender ; bark very thin, 

 deciduous, white, formed of scales ; polype-cells very far apart, ex- 

 serted, with eight valves. 



Tliesea exserta, Duchass. Sf Michel. Corall. Antilles, p. 18 ; Kolliker, Ic. 

 Hist. p. 137, t. 17. f. 18 (spicules) {not G. exserta, Solander Sf 

 Ellis). 



Hah. West Indies. 



152. Thesea guadalupensis. 



Thesea guadalupensis, Z)j<c/«flss. i^- Michel. Corall. Antilles, Suppl. p. 106, 

 t. 2. f. 2, 3. 



■ Coral branched ; branches flabellate, not coalescing, subequal, 

 slender, rigid, few in number ; bark white ; cells siibalternate, 

 distant, like mammae. 

 Hah. Guadaloupe. 



C. Polype-cells cylindrical or clavate, opposite, diverging from the branches 

 in two lateral series. 



75. STENELLA. 



Coral fan-shaped, in one plane, branched ; branches furcate, radi- 

 ating, slender. Bark thin, of thin scales. CeUs cyhndiical, opposite, 

 in a series on each side of the branches, projecting nearly horizontal, 

 covered with large scales, and closed with three horizontal valves. 



153. Stenella imbricata. B.M. 



Primnoa imbricata, Johnson, P. Z. S. 1862, p. 245 ; Ami. ^- Mar/. Nat. 

 Hist. 1863, xi. p. 299. 



" 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 ^vith small white scales composed of car- 

 bonate 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 sjjecimens of this elegant Primnoa have been obtained, the 

 larger of which has a height of 8| inches, with a width of 11 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 principal 



