132 Transactions. 



Art. XXIII. — Description of a Collection of Actinians from the Kermadec 



Islands. 



By F. G. A. Stuckey, M.A.. Wellington. 

 [Bead before the Wellington Philosophical Society, 21th August, 1913.] 



The specimens were collected by Mr. W. E. B. Oliver in 1908. They include 

 three New Zealand forms previously described, and four species which are 

 new to science. The three forms already known are Actinia tenebrosa 

 Farquhar, Phlyctenactis retifera Stuckey, and Paractis ferax Stuckey. 



The distribution of Actinia tenebrosa as given by me (1908) limited the 

 species to Stewart Island and the neighbourhood of Cook Strait. Since 

 then Professor Kirk has informed me that he saw it on Auckland Island ; 

 so that the distribution of the species may be set down as from the 

 Kermadecs to Auckland Island. 



Mr. Oliver's discovery of Phlyctenactis extends the distribution of the 

 genus as from Kermadec Islands to Stewart Island. 



In my original description of Paractis ferax, by a clerical error, I gave 

 the number of mesenteries as 32 to 36 pairs. The species has 24 pairs, 

 of which 6 pairs are perfect and fertile. Two pairs are directives. The 

 mesenteries of the second and third cycles are feebly developed. The 

 perfect mesenteries are as described and figured by me (Trans. N.Z. Inst., 

 vol. 41, p. 388). The chief points in the diagnosis of the species are the 

 muscular body-wall, the ectodermal invaginations and pits in the wall, and 

 the regular hexamerous development of the mesenteries. Mr. Oliver's 

 specimen is larger than any found by me, being 9 cm. in height. This 

 species was found by Mr. Walton in Manukau Harbour, so that its known 

 distribution is Kermadecs to Cook Strait. 



The following are the names of the species that are new to science : 

 Zoanihus atroviridis n. sp., Isaurus fuscus n. sp.. Epizoanthus oliveri n. sp., 

 and Metridium canum n. sp. 



Zoanthus atroviridis n. sp. 



The collector describes this species as follows : " Dark green. A very 

 slimy form occurring in large dense patches up to half a metre in diameter 

 in rock-pools between tide-marks, Meyer Island. The individuals when 

 expanded touched one another, thus entirely covering the rock-surface, 

 and the colonies were mostly on the northern side of the rock-pools, where 

 they would receive a minimum of sunshine." 



Form. — There is a fairly thick encrusting coenenchyme, on which the 

 polyps are arranged in groups rather than in lines or rows. The 

 coenenchyme, as well as the body-wall, is covered with sandy particles. 

 The polyps are of varying size, but all stand well up from the surface of 

 the coenenchyme. 



Dimensions (of largest specimen, contracted). — -Height, 30 mm. ; dia- 

 meter, 6 mm. ; capitulum, 10 mm. in diameter. 



Body-wall. — In structure and in historical character the body-wall 

 closely resembles that of Z. jitkesii (Haddon and Shackleton, Trans. R. 

 Dublin Soc, Dec, 1891). A remarkable character is the great thickness of 

 the mesogloea. 



Sphincter Muscle. — There is a well-developed mesogloeal sphincter, very 

 long, and tapering downwards. 



