650 MR. J, E. Dr"EEUKIf ON THE EELATIONS OF 



mesenteries, I find a pair of directives alternating with each: 

 pair of ordinary mesenteries, there being thus four pairs of 

 each, the arrangement recalling that which McMurrich found in 

 specimen No. 7 of S. spongicola. No gonidial grooves are here 

 distinguishable. 



In the same contribution special reference is also made to the 

 cases of Hicordea Jlorida and Shodactis Sa7icti-Thom(B. No 

 directives were found in one specimen of the former, and but a 

 single pair, situated to one side of the long axis of the stomo- 

 diBum, in another. In the latter species one pair of directives 

 was met with in two specimens, while in a third none were 

 discernible. As to these irregularities, my results agree with 

 those of McMurrich. No directives were distinguishable in two 

 young specimens of 'Ricordea, but in another two pairs were 

 disclosed. In several polyps of Bhodactis I was able to definitely 

 ascertain only one pair. 



Corynactis myrcia possesses eight pairs of perfect mesenteries,, 

 of which two pairs are directives. They represent the first and 

 second cycles, and eight alternating pairs represent a third cycle. 

 In the upper part of the stomodiBum, an odd member of the free 

 series may be complete for some distance. Tliis is esj)ecially 

 noticeable in the region of the pairs of directives. 



Some specimens of C. australis possessed only one pair of 

 directives, while another displayed two pairs. The arrangement 

 and number of pairs of perfect and imperfect mesenteries on each 

 side are very irregular, Kwietniewski found two pairs of directives 

 in G. carnea. 



Summary. 



The following is a recapitulation of the characteristics in the 

 possession of which the Actiniarian genera Corynactis^ 'Rliodactis^ 

 and Hicordea exhibit decided Madreporarian aflBnities. 



CoETiirACTis. — The occasional retention of a thin connecting 

 ccenosarc in asexual reproduction ; tentacles with a conical stem 

 and a globular head ; no gonidial grooves ; mesenterial filaments 

 simple, the Drlisenstreif only being developed ; large oval nemato- 

 cvsts; mesogloea practically homogeneous ; endodennal muscula- 

 ture and sphincter weak, the mesogloeal surface supporting it 

 being only sinuous or slightly folded; tentacles and mesenteries 

 tetramerous. 



