H»4 KKCENT MADRKI'OKAKIA DF THE HAWAIIAN ISLANDS AND LATSAN. 



loiiiiitiKlinal sections of the coralliti's. The inwanl iiic'linatioii of the septal trabeculae 

 ultiiuately l.riii<,'s their inner ends into an axial position, i. e., the eolumellar papillae 

 terminate trabecuhe which lower down occur in the septa. It thorefoi-e follows that 

 there is .some confusion between the pali and the i)apilLT. There is fusion among 

 the axial teetii l)V means of lateral processes, and there is some sclerodermic 

 c()mpactiu<>" of tlie mass. 



The skeletal surfaces hear a few, but not alnindaiit "granulations, in general 

 l)resenting a rather smooth appearance. 



Locality.— Kiun^oho, Oahu; de))tii. M to i; feet; icceiv.^d fiom W. T. Brigham; 

 also another .specimen, collected by Dr. ,1. E. Duerden at the same locality. 



Type.— Cut. No. 20954, U.S.N.M. 



lieiiiiirks. -This sp(>cies differs utt(M-ly in its septal composition, its pali. and its 

 coliunellar characters from any other Hawaiian I'orltcx. No other species shows so 

 definitelv that its septa are composed of inwardly inclined trabeculaj. Its septal 

 structure first led me to tliink that Bernard's elucidation of the morphology of the 

 Poritid septum should probsibly be modified. An examination of sections of other 

 species, broken parallel to the septal surface, showed that in other species, although 

 the septal, mural, and palar ti-abecuhe may run for Idiig distances in parallel courses, 

 from place to place a septal tral)ecula bends inward and a new one is introduced 

 between the older one and the wall. In these Poritids, that portion of the septum 

 exterior to the line of divergence of the trabecuhe is suppressed, while the inner 

 portion is developed. In I'oritis ihiirdeni the angle of divergence of the trabecuhv is 

 relatively^ large (the u])per angle between the wall and the. trabecula); in other 

 species, as /'. coiii-pn-nxd, the angle is extremely acute. The septal structure of the 

 Poritids is therefore entirely homologous with that of other corals. The .septa are 

 compo.sed of ascending trabeculfe, between which are numerous perforations. The 

 central corallite of Plate LXXIX. fig. \ii. shows the inward inclination of the 

 trabecuhe. 



4. PORITES EVERMANNI, new species. 

 Plate LXXX; Plate LXXXI, fig. 2. 



Desi-ripfiim of type. — Coi-alluni forming comjjressed or coluniniform lobes, 

 nodose around the base. 



The (•alices are shallow or superficial, with pali, except on and near the summits, 

 reacliing the level of the upi)eredge of the wall: outlines polygonal; diameter, from 

 1 to 1..5 nmi. Corallite walls very distinct, niembvaniform, forming narrow ridges 

 circumscribing the calices, rendered more prominent by the excavation of the distal 

 enils of the septa. 



The septa .show the typical poritid bilaterality : the usual arrangement is, a soli- 

 tary directive, two lateral pairs on each side of the plane of symmetry, and a ventral 

 directive with the lateral .septa fused to it by tlieii- iiuier edges. The principal varia- 

 tion occurs in the directive triplet. The arraiiVement was studied in CO calices with 

 the following result: Calices with five pali. 1; with six pali, 47; with seven pali, 1'; 

 with eight pali, '',; that is, 4 calices in .5 have six pali, or only one pains before the 

 ventrid tripl(>l; about 1 in 6 has two of the members of the triplet with separate 

 pali; and about I in 20 has pali on each mend)er of triplet. ,The palus on the 

 dorsal directive may be much reduced in size. According to the data given above, 1 



