18(5 RKCENT MADKKI'OKARIA VV THE HAWAIIAN ISLANDS AND LAYSAN. 



The I'aliccs arc rather large, from l.'Jo to -2 mm. in diameter, usuall.v about 2 

 mm.; shallow, or even superlieial. separated hy rather definite, low, ragged, thin 

 walls, 'i'he mural denticles are very rouyii. irregular, compressed, or twisted, and 

 ahout twice as uuiuerous as the septa. 



The septa are thick, thicker than lh<' wiilth of the interseptal loculi. Between a 

 l)alus and tlie wall there may he either one or two septal trabeculffi. It is ditficull to 

 decide which is the prevalent luuuher, each is frequent, two is probably the com- 

 moner in large calices. 'i'he trabecuhe have corresponding granules on the septal 

 margins. The outei- graiude when two are present, or the single granule when there 

 is only one, is detaciied from the wall and separated from it by a sinus: the ring of 

 granules is usually joined by a complete ring of synapticula, ordinarily slightly 

 distant from the wall, 'i'he outer ends of the septa, be^yond the synapticula, are 

 frequentlv bifurcated, 'i'he upper edges of the septal granules and the pali reach 

 the same plane and are almost as tall as the wall. 



The pali are rather thick, not very tall, although their upper ends reach so high 

 a level. Seven is the usual number. They are present before the lateral pairs, the 

 dorsal directive', and each lateral of the triplet. The formula is occasionally, but 

 rarely, complete. The palar ring of synapticula is constantly complete. 



The columella is a narrow, eompi'cssed style, not so tall as the pali. to which it 

 is joined by thick radii. 



The interseptal loculi are extremely nairow, because of the thickening of the 

 ditl'erent skeletal structures. 



The skeletal surfaces are roughly and coarsely granulated. 



Locality. — Kahana, Oahu; received from W. T. Brlghani: depth. :> to ti feet. 



Type.—(^&t. No. 21269, IJ.S.N.M. 



Hetiiurl's. — Forma divarlcans i.s characterized chiefly by its shallow or superHeial 

 calices, of somewhat greater diameter than is usual in the species, and the frequency 

 of two septal granules. 



PORITES COMPRESSA forma ELONGATA Dana. 



Plate LXXVI, figs. 1, \(i. 



184t!. Poi-lle-t tiiordd.r fi elnii;/<itii Dana, /Cuopli. Wilkes p^xpl. Exi>ed., p. 553, pi. Lin, fig. 4. 



Original duxeriptio i. — Dana's original description is as follows: 

 Tfiis figure [cited above] represents a specimen eight inches high, consisting of three or four stout 

 stems from a common base, which is two inches through and sparingly branched above. The upper 

 branclies are two to three inches long, an inch thick at base, and half an inch at apex. The cells are 

 very similar to those of the above [P. mordax\, yet a little smaller, about ten being counted in half 

 an inch. 



One of Dana's specimens is in the United States National Museum, it agrees 

 closely with the original description, but evidently is not the one that he figured. 



The following description is based ujH)n it. 



The corallum consists of .several rather stout branches rising from a conuuon 

 ba.se and girdled by irregular eon.strictions. Height, 16.2 cm.; di.stance between 

 divisions of branches, 2.:i cm. to 4.5 cm.; length of terminals, 2.5 cm. to -t.O cm.; 

 greater diameter of a main stem at base, 2 cm., lesser, 1.5 cm.; greater diameter of 

 a terminal at base, 1.2 cm., lesser, 1 cm.; greater diameter of terminal at tip, 0.9 

 cm., lesser, 0.7 cm. The ends of the branches are truncate, or obtusely rounded. 



