IIO PATERS FROM THE DEPARTMENT OF MARINE BIOLOGY. 



Identification is based on a photograph of Ellis and Solander's type, kindly 

 sent me by Professor J. Graham Kerr, of the University of Glasgow, Dana's original 

 specimens, and Matthai's figures and description. 



Stations, Murray Island. — Southeast reef, line I: 



1,630 feet from shore; water about 15 inches deep at lowest tide: hard, rocky bottom. 

 1,775 feet from shore, Lithothamnion ridge. 



The specimen from 1,630 feet from shore (plate 40, fig. 5) has thicker inter- 

 corallite walls and more crowded septa than those of the two specimens from the 

 Lithothamnion ridge (plate 40, fig. 4), having more the fusco-viridis facies. The 

 specimens from the Lithothamnion ridge so closely resemble F. hahcora in some of 

 their characters that I have vacillated between referring them to that species and 

 to F. abdita. They appear to belong to the latter. 



The succeeding notes are on Dana's types: 



Astrcea robusta Dana (type, No. 63, U. S. Nat. Mus., plate 40, fig. 1) is nearly typical 

 Favltcs abdita. The walls between the corallites are thickened below the upper edges, which 

 are usually acute; occasionally flat and wide, up to 3 mm., near the margin of the corallum. 



Jstiua Hexuosa Dana (type, No. 27, U. S. Nat. Mus., plate 40, fig. 2) has large, deep 

 calices, up to 18 by 14 mm. in diameter and 8.5 mm. deep. Intercorallites wall thick on 

 summit, up to about 4 mm., in some instances with a sulcus on top; between a few calices 

 near one edge of the corallum it is acute. 



Astrcea fusco-viridis Dana (pleisotype No. 28, U. S. Nat. Mus., plate 40, fig. 3), is 

 similar to the type of A. robusta, except that the specimen is young and has not assumed a 

 lobate growth-form. 



As all these specimens are similar in having subequal outer septal ends, similar 

 septal dentations, similar septal groupings, and similar columellar characters, they 

 can be regarded as representing growth facies or growth stages of only one species. 



Habitat and color, Cocos-Keeling Islands. — Dr. Wood Jones has obtained speci- 

 mens of this species in Cocos-Keeling, and made the following note: 



Two fragments of the same colony from a composite rock-mass in the lagoon; not at all 

 a common coral; it appears to be far more abundant on the south side of the atoll. Color, 

 zooid a very fine, vivid green, the coral itself yellowish. 



Distribution. — Red Sea; Indian Ocean; Pacific Ocean, eastward to Fiji Islands. 



Favites halicora (Ehrenberg). 

 Plate 41, figures I, 2, 3, specimens from Murray Island. 

 1914. Favia halicora Matthai, Trans. Linn. Soc. London, 2d ser.,Zool., vol. 17, p. 106, plate 26, figs. 3, 5-7. 



Five specimens are referred to this species, and as they exhibit interesting varia- 

 tions they will be described in detail. 



(1) Two specimens, southeast reef, line I, 1,400 feet from shore. 



Specimen A (plate 41, fig. 2), growth-form initially incrusting, becoming massive, the 

 size of a man's fist or somewhat larger. Upper surface rounded, not hillocky. 



Corallites polvgonal; calices polygonal, with rounded angles. Greater diameter up to 

 13.5 mm., average for a fully developed calice about 12 mm.; lesser diameter 10 to 12 mm. 

 Margins not elevated. Depth about 3 mm. Thickness of intercorallite walls, 2 to 3 mm.; 

 walls flat on top or with a very slightly raised, sharp edge. Outer ends of septa produce 

 slightly prominent costae which uniformly alternate in thickness. This alternation of the 

 septa in thickness is a striking feature. Frequently costs of adjacent calices are continuous. 



Septa in a mature calice thickened in the thecal ring; 24 reach the columella; 9 are well 

 developed, but do not extend to the columella; most of the septa of this size fuse near the 

 columella to the side of those of lower cycles, sometimes forming a triplet. In another 

 calice 21 reach the columella. Regularly alternating with the larger septa are small, short, 

 thin septa. The septal margins usually slope to the columella. Margins of the larger septa 

 coarsely dentate, 5 or 6 dentations on each inside the calicular cavities. Over the wall the 



