136 KECKNT AtAnUEI'OKAKIA OF THE HAWAIIAN ISLANDS AND LAYSAN. 



Tho .•olliiios ar(>. as lias hocn said, llattoiHHl. Iliore are no crests, and are crossed 

 by the septa-costa>, wliicli are crowded and reoulurly alternate in height. 



The usual number of septa for <'iich <ali<v is twelve, two cycles, of which the six 

 primaries are decidedly the larger and more prominent, and join the columella by 

 their inner ends. In some calices two. or even more, of the secondaries may reach 

 the columella; where this condition i)revails septa of the third cycle are present. 

 The edges of th(> septo-costal portions of (lie septa lie in a plane, and are microscop- 

 ically denticulate; the inner margins fall al)rui)tly to the bottom of the calicular fossa 

 and appear to be entire. The faces of the septsi and of the septo-costiB are minutely 

 granulated. Roth synapticula, which are rather scarce, and thin dissepiments, which 

 are abundant, occur in t\w intersepta! loculi. Tlie texture of the corallum is light. 



The columella is compressed, often lamellate, and situated in the bottom of a 

 narrow, rather deep calicular fossa. 



Local it I/.— Fnkoo, Moiokai, 2 specimens; depth, 3 to 6 feet; received from 

 W. T. Brigham. 



Coti/j)es.— Two specimens, Nos. 2ir,3() and 21631, l\S.N.M. 



JleniarJi-K.— There is a decidedly puzzling group of species, apparently belong- 

 ing to the genus I'dnma^ which comprises Pavona daws Dana; 2 undescribed 

 species represented l)y sp(>cimens in the United States National Museum, one 

 from Funafuti and the Tauuiotus, the other from the Galapagos Islands; Pavona 

 clivosa Verrill. from Panama, and the species here described. It is almost certain that 

 S. mahlivenxis (iardiner belongs with them, and most probably some of the specimens 

 from the Paumotus in the United States National Museum which I have tentatively 

 referred to /*. latiHteUata Dana. These species are characterized by having distinct, 

 continuous, coralliti' walls, which on the growing edges or the apices of the coralla 

 often exist sej)arately. In these areas synapticula may be present, both exothecally 

 and endothecally. Subsequently, by the deposition of stereoplasm, the individual 

 eorallite walls and the synapticula are united into a t'ompact wall. Pnrona g'ujantea 

 Verrill. from Panama, has around its older calices walls similar to those around the 

 older calices of the previously mentioned species, but along its growing edge the 

 walls can be seen to originate as synapticula, peripherally placed around the eorallite 

 cavity, which later fuse, forming a kind of theca. The eorallite walls of P. (/igantea 

 are morphologically the same as in P. crihtata (Ellis and Solander), /'. lata Dana, 

 P. era-s.sa Dana, /'. j>r;ttorfa Dana, etc. 



Two of these species, /'. clartm Dana and Siderastrea laaldivensis G&vdmev, have 

 been referred to the genus Sideradrea, type-species Madrepora rad'tana Pallas; and 

 the}' superficially resemble that genus. Upon closer scrutiny an additional resem- 

 blance is found ill the distinct, continuous eorallite walls, but there are important 

 differences. The septal margins of the species discussed in the foregoing remarks 

 are entire or microscopically dentate, and the septal lamellae are absolutely solid. In 

 the 5 or 6 species, specimens of which I have studied, there is persistently a lamel- 

 late columella or a compressed styliform columella. The septal margins of Sider- 

 astrea are pi'onovncedl ij d^mtate, the dentations rounded, one dentation corresponding 

 to each septal trabecula. The younger septa are distinctly perforate^ the perfora- 

 tioiis not heing conjined to tJw inner edgex. According to the valuation of characters 

 at present accepted for the Fungida, the species typified by P. claws Dana, etc., 



