210 KECKNT MADKKI'OKAKIA OF THE HAWAIIAN ISLANDS AND LAYSAN. 



Till' loo.-e, trabtriilar striu-tuiv ni tin- walls and the l.raii.-hcd sjiiiiuU-s that cover them gives the 

 upper surface a soft, almost woolly appearance. 



I'erhaps this species belougs with Poritea porosa Verrill, from the (_iulf of California (I. c, ji. oU4), 

 the description of which answers well for the specimen before me, but an identifieation without com- 

 parison appears too uncertain. 



Laysan. 



There is in the Yale University Museum an excellent specimen of this species, 

 which rrofessor Vcnill has Uindly loaned me, and thus enabled me to present figures 

 of it. Plate LXXWIII. lios. 1, \a. It has one, rarely two, trabecuhe between a 

 palus and the wall, ondino- in a tall upright tooth. 



Professor Studer has sent me a photog-raphic print of his type of this .species. It 

 alsi) possesses a septal arrangement similar to /'. hihata. The inner ends of the septa 

 of the ventral triplet do not fuse together, although they are joined by the palar 

 synapticula. Pali appear to l)e present before the dorsal directive, the lateral pairs 

 and the ventral directive. There are at least two rings of synapticula within the 

 walls, the mural and the i)alar. 



10. PORITES STUDERI, new species. 



Plate LXXXVIIJ, tigs. 2, 2((. 



Corallum subspheroidal. the three diameters, 28 mm., 25 mm., and 2ti mm., 

 respectivel}", surface rouiuled: no scar of detachment. 



Calices polygonal, diameter 1.5 to 2 mm., excavated but shallow. They are 

 separated on the surface by a slightly raised moniliform wall, which is usually con- 

 tinuous and straight. When the flat surface is looked at clo.sely perforations are dis- 

 cernible. Within the calice, very near the wall, is a zone of thickened synapticula 

 forming a continuous ring. This zone of synapticula may equal the wall in thickness. 

 A section near the level of the bottom of the calices shows that the wall between the 

 calices and the synapticular zones, one on each side of it, may become so thickened 

 that the three fuse together, very nearly obliterating any pores. 



Se])tal arrangement is four lateral pairs, the solitary directive, and, although the 

 inner ends of the laterals in the triplet approach the ventral directive near the col- 

 lunella, the usiiiil condition is for their surfaces not to meet. 



The septa are wedge shaped, with decidedly thick outer ends, becoming thinner 

 toward the cohuuella. Around the columella as a rule there is a second, an inner 

 synapticidar ring, and there is also much thickening of the septa below the bottoms 

 of the calices. The iriterseptal loculi are narrow; below the calices in some instances 

 they are almost obliterated. 



The septal margins slope gently to the bottom of the calice, without a nari'ow 

 upi)er and outer portion. On the wall is a dentation or knot corresponding to the 

 outer end of each se))t-um. The ])ali are small, crowiled down around the columella, 

 seven or eight in number; sometimes ab.sent on the ventral directive. Outside of 

 the palar ring and within the wall are from two to four dentations; two or three 

 appear to be the usual number. These dentations are irregular in shape, and theiu- 

 .sclves are minutely spinulose; one seems to be the usual number of septal trabecule. 

 Each septal face shows two or three gramdations, usually with blunt ends, l>etween 

 the palar ring and the outer .synapticidar zone. 



