ALCroNARIA— J. A. THOMSON AND DORIS L. MACKINNON 17$- 



Family GORGONELLID^. 



Genus CTENOCELLAi", Valenciennes. 



OTENOCELLA PECTINATA, Pallas. 



(Plate Ixxxi.) 



Ctenocella pectinata, Pallas, Elenchus Zooptiytoium, 17G6, p. 179. 



Ctenocella peclinalo, Ridley, Zool. Coll. H.M.S. "Alert" ISS't 

 p. 348. 



Ctenocella pectinata, Wright and Studer, Chall. Rep., Zool.. xxxi.. 

 lS89,p Ixvi. , 



Stations 34, 42, 44, 4V. 



There are several very perfect colonies of typical lyre-shape ; 

 they are all in the dried condition. The height of the largest 

 specimen is 50 cm., with a width of 42 cm. From a slightly 

 encrusting base rises a cylindrical stem, 7 mm. in diameter, 

 which soon forks. The two branches thus formed diverge at an 

 angle^of 45°, and give oiF, along the upper side only, a series of 

 parallel, ascending twigs. The space between two twigs is about 

 8 mm. One or two of these lesser branches may be stronger 

 than the rest, and may give off numerous ascending twigs in turn, 

 or fork dichotoniously. More generally, the branche.-; are simple, 

 from 4-12 cm. in length, and with an almost uniform diameter of 

 2-3 mm. 



The axis is light brown, and strongly furrowed. The ccen- 

 enchyma is thin, but very compact and smooth ; in many places 

 a distinct median furrow can he made out. 



The polyps have, on the twigs, an irregular bihiteral nrrHnge- 

 ment, but on the larger branches they occur all over the surface. 

 They are very numerous, about 05 mm. apart, and are all retracted' 

 into very low, wart-like verrucas. 



The spicules include the following types : — colourless double 

 clubs — 068 X •034 mm.; 051 x 034 mm.; a few crosses — 051 x 

 ■051 mm.; -034 x 0-34 mm.; and more elongated forms approach- 

 ing double-spindles, with scarcelv any "waist" — '085 x •OJSmm.; 

 •06S X 0-25 mm. 



The colour of the specimens is creara-wliite to ycllowisli. 



Locality. — Eleven miles east of Broken Bay. 



Previously recorded from Indian Ocean, seas of the Moluccas, 

 India and China, Cuba, Australia (Warrior Reefs, Torres Strait, 

 12 fathoms ; off N. W. Cape, W. Australia, 3-4 fathoms). 



^o In his " Revision of the Gorgonellidic " (Croc. Roy. Irisli Academy, 

 1910, p. 319), Mr. .). J. Simpson has shown convincingly that the genus. 

 Ctenocella shoiilii be merged in Srirjiearia. 



