Verrill, Notes on Radiata. 463 



OulactiS Edw. and Haime. 



Metridium {pars) Dana, Zooph., p. 150, 1846, {non Oken). 



Ouhctis E. and H., Corall., vol. i, p. 292, 1857 ; pars, Duch. and Mich., Corall. des 

 Antilles, p. 46, 1860. 



Column covered with verruciform suckers. Disk broad ; simple 

 tentacles placed at some distance from the margin ; outside of them a 

 circle of numerous, large, frondesceut, branchiform organs. 



Oulactis COncinnata Edw. and Haime. 



Metridium concinnutum Drayton, in Dana, Zooph., p. 152, PI. 5, fig. 40 and 41, 1846. 

 Oulactis concinnoM E. and H., Corall., vol. i, p. 292, 1857. 



Column low, broad, dilated above and below. Disk very broad, 

 strongly radiate, margin undulated, sides covered with large tubercu^ 

 liform suckers, to which pebbles and fragments of shells adhere. Ten- 

 tacles half an inch long, stout, subulate, sub-triangular, the lower side 

 slightly concave. Branchiform organs nearly 'o of an inch long, 1 to 

 I'o lines broad, frondescently laciniate. 



Column ochreous olive, with olive-green suckers ; three branchiae of 

 a white color alternate with a brown one ; simple tentacles similar to 

 column, but paler, faintly striped with pale purple^ disk purple. An- 

 other variety has the column green, with ochreous suckers. Diameter 

 at middle, in expansion, 2 inches ; at disk 3. 



San Lorenzo, near Callao, Peru, buried to its tentacles in sand, — 

 U. S, Exploring Expedition. 



Lophactis Verrill, gen. nov. 



Column elevated ; its walls firm, sub-coriaceous, in contraction rough 

 with deep corrugations and wrinkles, not verrucose, and without ap- 

 parent suckers in the preserved specimens. Simple tentacles large, 

 placed at a considerable distance from the margin. Branchije few in 

 number (12), arranged in a circle between the margin and the tenta- 

 cles, large and broad, laterally compressed, the upper edge of each 

 bearing a series of finely subdivided pajiillie, which consequently form 

 radiating rows of secondary branchiae. The large branchiform organs 

 are united together on the side nearly to their summits by a thin 

 membrane, which forms a naked area between the branchiae and ten- 

 tacles, and they are also united on the outside by adherence to the 

 marginal fold, so that, when contracted, there are deep chambers or 

 cavities between them. 



This genus is closely allied to Phyllactis, but the latter has more 

 numerous branchia?, which are quite difierent in structure, and are 



Teans. Connecticut Acad., Vol. I. 59 February, 1 869. 



