Io6 PAPERS FROM THE DEPARTMENT OF MARINE BIOLOGY. 



Inner ends of the principal septa bear distinct, usually tall and erect, paliform teeth, 

 which are pointed or rounded 



Columella trabecular, of loose texture, diameter about one-fifth that of a calice; in a 

 depression surrounded by the paliform teeth. 



Exotheca composed of thick-walled vesicles; endotheca composed of sloping, curved 

 dissepiments, from 0.75 to slightly more than i mm. apart. 



Reproduction by unequal fission. 



A specimen in the U. S. National Museum, No. 77, which bears the label 

 " Astrcea celhilosa Ver., Pacific Ocean, U. S. Expl. Exped.," appears to be a part of 

 the original specimen of Dana's Astraa denticulata, which was Verrill's type. The 

 following description is based on it: 



Corallum massive; the type is a damaged specimen which evidently exceeded 10 cm. 

 in length and 4 cm. in thickness. 



Calices subcircular, elliptical, or oval in transverse outline; lesser diameter about 8 mm., 

 greater diameter up to 10 mm., in calices not yet dividing. Depth up to 3.5 mm. Margins 

 slightly elevated, occasionally as much as 2 mm., usually less. Distance apart from 2 to 

 3.5 mm. Intercorallite areas furrowed, across the bottoms of which costae from adjacent 

 calices in many instances are continuous. 



Costae correspond to all septa, and frequently small ones have no corresponding septa. 

 Alternately large and small. Edges dentate, dentations compressed in plane transverse 

 to that of septum. 



Corallite walls thick; between corallites a few thick-walled exothecal vesicles. 



Septa thickened in the thecal ring, thinner within calice; in a large calice, 8 by 10 nun. 

 in diameter, 17 principals, 12 shorter but well-developed, and a number of very rudimentary 

 septa, which are usually represented by small costs' on the thecal edge. Average 12 or 

 I or 2 more principal septa. Upper margins of principals exsert up to I mm., arched, 

 dentate, dentations fairly regular, others not so exsert; inner margins sloping or vertical, 

 with rather long dentations, longest near the pali. Faces with small, conical granulations. 

 From 6 to ii tall, erect, stout paliform teeth, which are pointed or rounded. 



Columella trabecular, poorly developed, in a depression surrounded by the pali. Diam- 

 eter 1 to 1.5 mm. 



Dessepiments slope slightly downward toward columella, thin, average about i mm. apart. 



Reproduction by unequal fission. 



Dana's original specimen of his Astraa versipora (non Lamarck) is No. 76, 

 U. S. National Museum, from Singapore. It is nearly the same as Favia pallida, 

 Facies 3, of the Murray Island series (see page 107, plate 38, fig. 4). The septa are 

 highly exsert, up to 3 mm. and have roughly dentate arches. The calices are deep 

 and the columella is weakly developed. Dana correctly observed the similarity 

 between this specmien and his Astraa denticulata, which was subsequently named 

 Favia cellulosa by Vernll. 



The Murray Island specimens present about 6 facies, each of which is described 

 in the following notes: 



Facies i (plate 38, fig. 2). 



Corallum massive, rounded above, size about double that of a man's fist. 



Calices subcircular or elliptical; diameter 7 to 8 mm.; distance apart i to 3 mm. Mar- 

 gins scarcely elevated, 1.5 mm. the maximum. Depth up to 4 mm.; usually less. Inter- 

 corallite furrows indistinct. 



Costae subequal, those of adjacent corallites usually but not invariably continuous; 

 sides vertical, in places exsert up to 1.5 mm.; interspaces up to 0.75 mm. wide. In some 

 places rudimentary costae, with or without corresponding rudimentary septa, intercalated 

 between the prominent costae. Edges with rather regular dentations, which are compressed 

 in a plane perpendicular to that of the septum. 



Septa in mature calices, 16 reach the columella, 10 well-developed but shorter, and 

 5 or 6 very small septa, not so many rudimentary septa as rudimentary costs. Usually 

 12 or a few more than 12 septa extend to the columella. The outer ends somewhat thickened 



