BULLETIN 09, UNITED STATES NATIONAL MUSEUM. 145 



and rather proiiiinoiit thickcniii<f of tho septa or septo-costie. Tliese tliickeiiin<fs 

 are not definite in occurienee, hut ai'o most t"re(juent peripherally. Tiie septal 

 faces are minutely granulate. Distally, between the septo-costse, synapticula are 

 very al)un(lant, readily visible when the corallite is viewed from above. The septa 

 are orioinaily linely trabeculate and fenestrated, l)ut beeome almost or entirely solid 

 by subsequent stereoplasmic deposit. 



The columella consists of a sinji-le. minute tul)ercle. situated in a small, shallow 

 central pit. 



Locality. — Kalaeloa, Molokai; depth :', to <! fathoms; 2 specimens received from 

 W. T. Brig'ham. 



Cotypes.—Oiit. No. 21637. I'.S.N.M. 



Genus BATHYACTIS Moseley. 



BATHYACTIS HAWAIIENSIS, new species. 



I'lato \XVII, lifTi^. 1, l.i. 



1905. Batlq/actis Stephana Vauohan, Science, n. .«. , XXI, p. 984 (not Ballnjarlin ntfjihana Alcook, 

 1893). 



Corallum with a subcircular. slightlj' concave base; diameter, 25 mm. The wall 

 is extremely thin, translucent, and imperfe(;t in places. Distant, thin, plate-like, 

 but low, costaj correspond to all septa, those corresponding- to the last cj'cle less 

 prominent than the others. Costal edges finely serrate. In the center there is a 

 small scar, 1.5 mm. in diameter, resembling a detachment scar. 



The calice is superficial. Septa extremely thin, in live complete cj'cles, form- 

 ing six septsil groups, one group between each pair of primaries. The tertiaries 

 fuse by a calcareous membrane to the included secondary, the ([uaternaries fuse 

 nearer the wall by their inner margins to the included tertiary, and the quinarics 

 to the included quaternarv. The primaries and secondaries are tall, projecting 8.5 

 or 9 mm. above the base. The outer edges of the margins descend perpendicularly 

 and connect with the costal ends beyond the limit of the wall. The tertiaries and 

 quaternaries are not nearly so prominent as the first two cycles, the quinaries are 

 relatively low. The margins are irregularly, rathei- l)luntly dentate, but are not 

 lacerate. The inner portion of the margins of tin' primaries and secondaries is 

 frecjuently divided by a sinus from the outoi', forming a broad paliform lobe. The 

 septal faces are fluted, with carina- bearing spinules along the flutes. There are on 

 the larger .septa about sev'en flutes in 5 mm. From rive to six synapticula occur in 

 an intcrseptal locuius. They are niemlManifonn and are connected with the septal 

 carinas. 



The inner ends of the septa are united liy a calcareous membrane, about 2.5 

 mm. in diameter, whose central portion is d(-presscd and thiough which a few- 

 slender spines from the inner ends of the septa pri)jcct. 



Localify.^Kaioie Channel, between Oahu and Kauai islands, Station 4125; 

 depth, 9<)3-1124: fathoms; bottom, brown mud. radiolaria. and foiaminifera: temper- 

 ature of the bottom. 3t».4^ F. 

 32301—07 10 



