950 THE VOYAGE OF H.M.S. CHALLENGER. 



6. Dendrocircus harbadensis, n. sp. 



Gate irregularly ovate or nearly semicircular. Eiiig of the same obUque form, thick, with 

 interrupted and distorted edges, armed with eight to twelve larger iiTegularly formed and branched 

 acute spines; between them numerous conical smaUer spines. This common species is very 

 polymorphous and variable. 



X>ime?mo»is.— Diameter of the ring 0-05 to 0-08 ; length of the spines 0-005 to 0-02. 



Habitat. — Fossil in Barbados. 



7. Dendrocircus stalactites, n. sp. (PL 81, fig. 14). 



Gate obliquely ovate. Ring irregularly ovate or roundish, very thick, vrithout edges, armed with 

 numerous (eight to twelve or more) short and stout branches, which are shorter than the diameter 

 of the oate, irregularly disposed and branched, with very numerous clustered blunt ramules. 



Dimensions. — Diameter of the gate G-07 to 0-09 ; length of the spines 0-02 to 0-06. 



Habitat. — Western Tropical Pacific, Station 225, depth 4475 fathoms. 



Subfamily 2. Cortinida, Haeckel. 

 Definition. — S tephanida with typical basal feet (or cortinar feet). 



Genus 405. Cortina,^ n. gen. 



Definition. — S tephanida with a simple dipleuric or bilateral ring, bearing at 

 the base three divergent feet (one odd caudal and two paired lateral feet). 



The genus Cortina and the following Stephatiium represent together the small but 

 very important group of Cortinida, differing from the simple Lithocircida in the 

 possession of three typical basal feet, which are transmitted to the majority of the 

 Nassellaria by heredity, and produce their peculiar trii-adial structure. They appear 

 therefore as a combination of the simple ring [Zygocircus) with three basal feet 

 {Plagonium). One of these three divergent feet is the odd caudal foot, op]30site 

 to the apical horn ; the two others are the paired lateral or pectoral feet. (On the 

 probable origin and the typical signification of Cortina compare above, pp. 891—894.) 



1. Cortina tripus, n. sp, (PI. 83, fig. 9). 



ELng ovate, smooth, or with a few short thorns. Apical horn obUque, curved, simple, smooth, 

 about as long as the sagittal axis of the ring. Feet divergent, curved, simple, smooth, about as 



1 Cortina = Tripod. 



