BULLETIN 59, UNITED STATES NATIONAL MUSEUM. 185 



Calices pol^'g'onal, avcraj,'-!' diaiiictcr al>oiit 1..") nun., ot' niddcratc dcptli, espe- 

 cially- on the upper part of the t)ranches; separated by slij^htly or considerably ele- 

 vated walls, wiiicli are tliin on the edjje, thicker below; with about twice as many 

 nitiier delicate, j^ijmulated nniral denticles as there are septa. 



The septa are uioderatcly thick, often e(]ualing or slij^htly exceeding in thickness 

 the width of the interse})tal locnli. lietween a palus ;uid the wall ther(! is normally 

 a single se])tal trabecula, whicii forms on tlie septal margin a prominent tooth, which 

 is eitlier an irregular granule, or is rather wide and lamellate and almost as tall as the 

 wall, from which it is considerably removed. Between this tooth and the wall is a 

 rather deep and persistently' j)rescnt sinus. Extending around each calicc; atid 

 reaching the level of the bases of the teeth is a ring of synapticula, usually almost 

 or entirely complete. The outer edge of the synapticuiar ring is sligiitly exterior 

 to the outer edge of the septal teeth, but it is usually detached from the wall, 

 thus dividing the interseptal loculi into two parts, an outer shorter and an inner 

 longer one. The outer ends of the septa are thicker than the inner. It is the 

 thickened outer ends of the septa, with their synai)ticular cotuiections, that give this 

 forma its rather compact texture, and have suggested tiie name that is attached 

 to it. 



The pali are thi<k pointed and prominent, reaching to the level of the upper 

 edges of the septal tooth. Six is the. most common number, pre.sent before the 

 lateral pairs and the two directives, but there is considerble vaiiation. The one 

 before the dor.sal directive is .sometimes suppressed, leaving otdy tivc; frequentU- 

 they are iiresent not only before the lateral pairs and the doi'sai directive, but before 

 each lateral of the triplet, the one before the ventral directive being suppres.sed; in 

 some calices the formula of eight pali is complete. The palar ring of synapticula is 

 very constantly c<implete. 



The columella rises from the bottom of a deep fossa, Iwundcd l)\ the perpen- 

 dicular iinier edges of the pali, to which it is joined by radial connections. It is a 

 compressed lamella, and is prominent, l)ut not so tall as the pali. 



The skeletal surfaces are covered with rough, rather couisc, irregular, but not 

 very closely set granulations. 



Localitij. — Kahana, Oahu; received from W. T. Rrigliaiu: de]ith, 3 to 6 feet. 



Type.—OA.t. No. 21l'7u, U.S.N.M. 



Memarhn. — Forma compacta difi'ers from the subsequently descrilied forma (//wcvm- 

 by its mori? compact skeletal structures and the greater fre(|ueiuy of incomplete- 

 ness in the palar fornuila. 



PORITES COMPRESSA forma DIVARICANS, new. 



Plate LXXV, lif.'s. 1, 1.,. 



Corallum composed of compressed, divergent branches, with truncate and some- 

 what swollen ends, nodulose on the sides. Hciglit of specimen. In.S.") cm.; greatest 

 spread (across three branches), lU.tt.5 em.; lengtii of longest branch, O.on cm.; 

 greater diameter of base, 3.2 cm.; lesser, 1. 5 cm.; greater diameter of swollen 

 tip, 1.1 cm.; lesser, 0.7 cm.; depth of living portion. (•..").■> cm. to 10.75 cm. 



