1586 THE VOYAGE OF H.M.S. CHALLENGER. 



Genus 669. Aulospathis,^ n. gen. 



Definition. — A ulacanthida mtli a veil of tangential needles, and with radial 

 tubes, which bear two verticils of branches, a distal verticil of terminal branches, and a 

 proximal verticil of lateral branches. 



The genus Aulospathis and the following Aulodendron differ from the preceding 

 Aulacanthida in the possession of lateral branches ; these are usually similar to the 

 terminal branches, and irregularly scattered along the distal half of the tubes in 

 Aulodendron. In Aidospathis, however, the largest form in the family, each tube bears 

 two whorls or verticils only, a verticil of terminal branches at the distal end, and a 

 verticil of lateral branches beyond the latter, between the middle and distal third of 

 the tube. The number of branches in each verticil is usually from two to four, rarely 

 more ; it is, however, very variable, so that the ten species described in the sequel are 

 "Darwinian species," derived either ivom. Aulospathis polymorpha or irom Aidospathis 

 variabilis. Each branch bears at the distal end a spathilla, the teeth of which are very 

 variable in form, number and arrangement. 



O" 



Subgenus 1. Aidospathessa, Haeckel. 



Definition. — Distal ends of the radial tubes inflated, usually in the form of an ovate 

 or pyriform terminal knob. 



1. Aidospathis hi/urca, n. sp. (PI. 104, figs. 1-5). 



Eadial tubes with an inflated ovate terminal kuob at the distal end, which bears two divergent, 

 curved, terminal branches (often a few tubes bear three or four branches instead of the usual two). 

 Proximal whorl usually cruciate, with four irregularly crossed lateral branches (but often with five 

 or six, more rarely with two or three). 



Dimensions. — Length of the tubes 015 to 25 mm., bi-eadth 0-04 to 0-06 ; branches Ol to 0-15. 



Habitat — South Pacific, Stations 293 to 295, depth 1500 to 2270 fathoms. 



2. Aulospathis trifurca, n. sp. (PI. 104, figs. 6, 7, 7a). 



Eadial tubes with an inflated ovate terminal knob at the distal end, which bears three divergent, 

 straight, or slightly curved terminal branches (often a few tubes bear two or four branches instead 

 of the usual three). Proximal whorl irregular, usually with six divergent, straight, lateral branches. 



Dimensions. — Length of the tubes 2-2 to 3-4, breadth 0-03 to 0-05 ; branches Ol to 015. 



Habitat. — South Pacific (off Valparaiso), Stations 298 to 300, depth 1375 to 2225 fathoms. 



' Aii,lospathis=T\ihii with whirls ; a.v>^6g, a-jrotSl;. 



