Stephenson — Certain Actiniaria collected off Ireland. 109 



Carlgrenia n. gen. 



Endocoelactidae with 6 pairs of macromesenteries bearing circumscribed 

 retractor muscles, filaments, and most or all of them gonads. There are 

 also representatives of 3 orders of mieromesenteries ; of these the first order 

 consists of 4 pairs, developed in the 4 lateral endocoels, and these 4 pairs 

 have the character of directives, i.e. their longitudinal muscles face away from 

 each other ; these 4 pairs run down ihe whole length of the body, and just 

 reach the actinopharynx at its upper end, but they bear neither developed 

 gonads, filaments, nor retractor muscles. There are other small micro- 

 mesenteries entirely confined to the uppermost part of the body. 



I have founded the above genus for a small but extremely interesting 

 form which is present in the collection. In a paper (8) on Porponia and 

 related genera, Carlgren made a suggestion which would account for the 

 descent of the 10-rayed forms contained in the Endocoelactidae from a 

 6-rayed form, by the appearance of 4 pairs of secondary mesenteries with 

 the character of directives, one in each of the endocoels of the 4 lateral pairs 

 of primary mesenteries, instead of, as usual, in all the exocoels. The above- 

 mentioned form presents so interesting a confirmation of this idea, that I 

 propose to honour it by conferring upon it the name of the distinguished 

 zoologist whose work in connection with Actiniaria is so well known. 



3. C. desiderata, n. sp. 

 (PL XIV, fig. 1 ; PL XVI, fig. 27 ; PL XIX, fig. 1 ; PL XX. figs. 2, 8, 9.) 



Four specimens. SE. 504. 12. ix. 07. Trawl. 627-728 fathoms : from 

 Lophohelia. 



I have been unable at present to work out the detailed anatomy of this 

 form as closely as I could wish, but it is so distinct a species that 1 think the 

 details which follow will be found to be sufficient for identification ; I hope 

 to publish fuller details at a later date. 



The specimens were taken from Lophohelia. They are small (the largest 

 measuring, in total length, about 2 cm.), and do not present any striking 

 external features. (PL XIV, fig. L) 



Pedal disc present, small, not much exceeding the column. Body no! far 

 from cylindrical, inclined to be rather wider above than below, soft in texture. 

 There is a slight marginal parapet and fosse, and sometimes the former is a 

 little notched. The whole surface is wrinkled and somewhat corrugated, bul 

 as far as I can see there are no actual vomicae. The whole animal is pale- 

 Brown in spirit, with darker shades pn throat, disc, and tentacle bases. 



