12 



WRIGHT and STUDER add to this description the character of the axis, which is really the 

 best diagnostic feature of the genus. After quoting VERRILL'S definition they add: 



"To this may be added that in the structure of the axis there is a general resemblance 

 to that of Plexaurella '. 



In spite of this "general resemblance", however, there is a very distinct difference between 

 the axis of Plexaurella and that of Euplexaura. In a cross section of a branch of a typical 

 species of Plexaurella the clear, horny core is surrounded by a thick envelope which is composed 

 of a number of long, vermiform, white calcareous bodies enclosed in a casing of chitin. In a 

 similar section of Euplexaura no such definite structure of the axis is seen; but there is a 

 central core of pure, translucent, horny material around which is a thick cylinder of horny 

 material extensively impregnated with lime salts. These latter sometimes seem to take the form 

 of fibres, but are not nearly so distinct and white as the vermiform bodies of Plexaurella. 

 The axis of the latter genus is excellently well illustrated by KOLLIKER, Icones Histologicae, II, 

 plate XIV, fig. 8. It has also been described and figured by the present writer *. 



KUKENTHAL has emended the definition of this genus in so satisfactory a manner that 

 we may adopt his diagnosis, which is as follows : 



"Kolonien in einer Ebene verzweigt. Polypen fast stets ohne gesonderte Kelche direkt in 

 das dicke Ccenenchym zuriickziehbar. Polypen stets mit konvergierenden Reihen von Spindeln 

 bewehrt, unter denen horizontal angeordnete liegen. Die Rinde enthalt an der Oberflache dicke, 

 meist ovale Spindeln und Doppelspindeln, die dicht mit grossen Warzen besetzt sind, darunter 

 liegen kleinere, schlankere Spindeln mit regelmassigen Dornengiirteln. Achse fast stets etwas 

 verkalkt und wenig biegsam. Die Farbung samtlicher Arten schwankt zwischen weiss, gelblich 

 und hellbraun". 



The type of the genus Euplexaura is E^^plexaura capensis Verrill. The other known 

 species are Euplexaura pinnata Wright and Studer, E. rhipidalis Studer, E. parciclados Wright 

 and Studer, E. anastomosans Brundin, E. curvata Kiikth., E. robusta Kiikth., E. crassa Kiikth., 

 E. abietina Kiikth., E. sparsiflora Kiikth., E. erecta Kiikth. , E. albida Kiikth., E. braueri Kiikth., 

 E. parva Kiikth., and the new species about to be described. 



i. Euplexaura rubra new species. (Plate III, figs. 3, 3^; Plate IV, fig. 7). 

 Stat. 164. i42'.5 S., 1 30 47'. 5 E. Near New Guinea. 32 meters. 



Colony incomplete, about 8 cm. long. The basal part is lacking, and it appears that 

 we have but the terminal portion of the main stem, or large branch, giving off two small 

 lateral branches on one side, and one on the other. The stem and branches are round in section, 

 the diameter of the former being 2.5 mm. and of the branches about 1.5 mm. The calyces are 

 rather prominent for this family, and are equally distributed on all sides of the branches. 



The individual calyces are coninal in form, a typical one measuring about i mm. in 

 height and 1.4 mm. across the base. The polyps are completely retractile, the summits of the 



1 NUTTING, Anatomy of the Gorgonidje, Bulletin from the Laboratories of Natural History of the State University of Iowa, 

 Vol. I, N 2, 1889, p. 129, plate II, figs. 8, 9 and 10. 



