CLASSIFICATION OF ACTINIARIA 307 



2. Thoracactis (1918, p. 12). T. topsenti, 1918, p. 12. 



A small form living on the surface of a sponge. It is disc shaped, in- 

 crusted, the foreign bodies even getting embedded in the mesogloea. 

 Sphincter mesogloeal, seemingly double. No acontia or cinclides. Weak 

 mesenterial musculature. 



Gravier believes that the gonads develop from the endoderm of the 

 body-wall. There is not much guide, but the form may be a tiny 

 Paractid or even, possibly, a Zoanthid ? 



3. Telmatactis (1916, p. 236). T. valle-flori, 1916, 



p. 286. 



This seems to me to be probably identical with Phellia, in which 

 case the species becomes Phellia valle-flori. 



4. Sicyopus (1918, p. 21). S. commensalis, 1918, p. 21. 



This lives on a Holothurian, in a hollow of its skin near the mouth. 

 It has the form of a thick disc, strong mesogloeal sphincter, no acontia 

 or cinclides, diffuse retractors, all mesenteries fertile. It seems like 

 a small Paractid of uncertain aflfinities. 



5. Gliactis (1918, p. 7). G. crassa, 1918, p. 7. 



Here the base envelops A c a n e 1 1 a . There are no verrucae, the 

 column wall is thick. Good mesogloeal sphincter. Apparently twenty 

 pairs of perfect mesenteries, probably diffuse retractors. If there are 

 no acontia or cinclides this seems eligible for one of the Paractid genera, 

 and probably does not merit generic distinction. 



T have not suggested very definitely about the above forms,. 

 but they are not all very fully studied as yet, and the time 

 has not come to decide for or against them ; but they will 

 probably fit into known families. 



In addition Professor Gravier has described ncM^ species in 

 old genera as follows : 



1. Paractis flava (1018, p. 4). Either a Paractis in the strict 

 sense, or belonging to a neighbouring genus. 



2. Paractis vestita (1918, p. 5) may have some sort of invest- 

 ment on the column, and seems to have only six pairs of perfect mesen- 

 teries, no acontia and cinclides, mesogloeal sphincter ; in which case 

 it is no Paractis, but an Actinoscyphid near Par an thus, perhaps 

 eligible for that genus. 



3. Actinernus verriUi (1918, p. 6) is not an Actinernus 

 ( =Porponia). since it has a mesogloeal sphincter and is apparently 



