178 RECENT MADKKl'ORARTA OF THE HAWAIIAN ISLANDS AND LAYSAN. 



uppor portion of tlic corallum is elevated, hut lUMir the l>:is<' it is reduced in heii;ht, 

 and the septal oraiiules are tali, soiuetinics almost eiiuuliny the wall in height, and 

 the outer ring- of synaplicuia may l)e almost complete. 



This forma is in its caiieular cliararters scarcely to he separated from I'orites 

 fuikoeiixix, new species (s(>e Plate XCI \' and Plate XCV, tigs. 1 , '1, p. 195). The columns 

 of the latter are thicker. l)ut the resendjiance in other features is so similar that their 

 ))eing dirterent growth forms of the same species is strongly suggested. 



Dr. J. E. Duorden ohtained at Waikiki, Oahu, a suite of over thirty specimens 

 of a Poritefi that seems to he a modilication of P. ('niiiprcxxa forma niKjustlseiita: the 

 form of the corallum, however, is usually rather ditl'erent. A description of the 

 development of the corallum will most (dearly hring out the essential chaiacters. 



The corallum in its early stages foruis over various ol)jects an iucrusting layer, 

 with gihhositie.s on its upper. >Sul)se((uently low crests and nodules appear. The 

 crests may develoi) into elevated plates, the nodules into stumpy, incrassate, nuudi 

 fused branches. The ititergradation from the corallum that is only a surface 

 incrustation to the morc^ ramose form of the forma is complete. A careful com- 

 parison of the ealices of the various specimens showed no important diiierences (see 

 Plate XCIII, figs. 1, 2,;^). 



PORITES COMPRESSA forma ANGUSTISEPTA subforma DELICATULA, new. 

 I'lale LXVIll, %. L'; Plate LXIX, tij:. 1. 



This sul)forma (litters from forma angmtiiiepta b}' its more delicate pali and the 

 crowded, fine, loiiif spinulations of the skeletal surfaces. Otherwise there is no note- 

 worthy diff'erence. The sides of the branches or plates possess rounded gibbosities, 

 but no particular importance can attach to them. 



Locality. — Pukoo, Molokai; received from W. T. Hrigham: depth, 3 to 6 feet. 



Type.— Cat. No. 2()!»29, U.S.N.M. 



PORITES COMPRESSA forma ANGUSTISEPTA subforma PAUCISPINA, new. 



Plate LXIX, figs. 2, 2a. 



This subforma is ba.sed on a single specimen, composed of se\ eral fused and flexed 

 plates, with nodose upper edges. Height, 5.45 cm.; length, 7 cm.; width, fi.'.t ciu.; 

 depth of living portion, from 1.75 cm. to 4.»i5 cm.; thickness of plate, 1.2 cm. 



The difi'erence between this specimen and forma (iiKjmtlsepta consists in the 

 sharper and more scattered septal granulations and a generally more lagged appear- 

 ance of the skeletal parts. The ealices average somewhat smaller, ranging in diameter 

 from 0.8 to 1.75, with ahout 1.5 as an average. 



/;om/%.— Pukoo, Molokai; received from W. T. Brigham; depth, o to 6 feet. 



%«.— Cat. No. 2(il»-42, U.S.N.M. 



PORITES COMPRESSA forma FRAGILIS, new. 

 Plate r>XX; Plate LXXI, figs. 1. \a. 



Corallum forming a head, ItJ cm. across, compo.sed of sinuous, anastomosing 

 plates, or compressed knobs, with tiuncated or rounded upper edges. Lesser 

 diameter of a knob, IS. 5 umi. 



