390 Transactions. 



Gonads. — Placed much, as in Paractis ferax, and form large masses between 

 the mesenteries. 



Dimensions. — Height, 40 mm. ; diameter, 30 mm. 



Distribution. — Of the genus — Antarctic Ocean (Delage and Herouard) ; 

 also New Zealand. Of the species — Island Bay. 



Fam. CORALLIMORPHIDiE. 



" Hexamerous Actinice with a double corona of tentacles, a corona of 

 marginal principal tentacles, and a corona of intermediate accessory tentacles. 

 Mesenteries slightly differentiated and all gonophoric. Muscular system 

 weak in all parts of the body. No sphincter." 



Genus Corynactis (Allman). 



The tentacles are all knobbed. They are arranged in radial series, so 

 that more than one communicate with each inter- or intra-raesenterial space. 



Farquhar described three species of Corynactis from the neighbourhood 

 of Wellington. These are C. haddoni (with seven varieties), C. ■mollis, and 

 C. gracilis. 



In external form these species are all very similar, their chief apparent 

 difference being in the matter of colour. I think it not unlikely that the 

 species and varieties enumerated by Farquhar may prove on investigation 

 to belong to only one species. I have not yet, however, been able to collect 

 specimens of all the species of C. haddoni, and have therefore to defer the 

 investigation. To the species mentioned above I add a fourth, C. albida. 

 In external appearance this corresponds closely to C. haddoni, except in 

 colour, which is pure white, without any deposit of pigment. The principal 

 tentacles are very long and slender, inclining slightly outwards in expansion. 

 The accessory tentacles stand upright. 



Farquhar has so carefully described the external appearance of his species 

 that there is no need for repetition here. I have not yet fully worked out 

 their anatomy and histology, but have made the following notes : — 



12. Corynactis haddoni (Farquhar). 



13. ,, gracilis (Farquhar). 



14. ,, mollis (Farquhar). 



15. ,, albida (sp. nov.). 



Mesenteries. — In all four species there are 24 pairs, of which 12 pairs 

 appear, typically, to be perfect. There is scarcely any indication of retractor 

 muscles in any species, but the parietal muscles are generally fairly well 

 developed. On the filaments in some sections I noticed the same appearance 

 of three trefoils as I have described in Actinia tenehrosa. 



Sphincter Muscle. — On account of the complete infolding of the tentacles 

 Farquhar supposes the sphincter to be well developed, and in this belief 

 he is supported by Delage and Herouard. A large number of longitudinal 

 sections of the four species under survey failed, however, to show the slightest 

 indication of a sphincter. 



C. haddoni : Though there is no sphincter, there is a fairly distinct circular 

 muscle in the wall. This consists of a few fibres running on the endodermal 

 side of the mesogloea. The mesogloea is homogeneous. The ectoderm is 

 the thickest of the three layers, the other two each being about half its 

 thickness. 



