122 PAPERS FROM THE DEPARTMENT OF MARINE BIOLOGY. 



evidence indicates that § A and § AA of Milne Edwards and Haime, plus //. conhg- 

 natio (Forskal), plus H. tenella (Quelch), are all only stages or growth-forms of one 

 species, //. exesa (Pallas). 



Distrihition. — Red Sea; Indian Ocean; Murray Island; Amboina; southern 

 Philippines; Funafuti. 



Hydnophora microconos (Lamarck). 



Plate 47, figures 3, 30, specimen from Murray Island. Also plate 18, figure 42, of Dr. Mayer's article. 



1857. Hydnophora microcona Milne Edwards and Haime, Hist. nat. Coral!., vol. 2, p. 423. 

 1907. Ilydnopliunila microconos Bedot, Madreporaires d'Amboine, p. 197, plate 25, figs. 1 19-122. 



Specimens of this well-known species were collected at Murray Island, south- 

 east reef, line I, as follows: 



1,600 feet from shore water 10 inches deep, a perfect head, attached by a pedicellate base (see plate 47, 

 figs. 3, 3a). Greater diameter 15 cm.; lesser, about 12 cm.; height, about 9.5 cm. 



1,640 feet from shore, water 14 inches deep at lowest tide; hard, rocky bottom. A piece of a thriving head. 



1,775 feet from shore; Lithothamnion ridge. Upper part of corallum killed and corroded; living around 

 the edge. 



Two beach-worn specimens were picked up by Dr. Wood Jones in the Cocos- 

 Keeling Islands. He did not observe the species alive. 



Distribution. — Red Sea; Indian Ocean; Murray Island; Amboina; southern 

 Philippines; Rotuma; Wakaya (Fiji Islands); Fanning Island. A good specimen 

 of the species collected by Mr. Carl Elschner at the last-mentioned locahty is in 

 the U. S. National Museum. 



Hydnophora rigida (Dana). 

 Plate 48, figure 2, specimen from Fanning Island; figure 3, part of Dana's type of Merulina rigida. 

 1846. Merulina rigida Dana, U. S. Expl. Exped., Zooph., p. 176, plate 17, figs, i, \a-ic. 



A figure of Dana's type is given on plate 48, figure 3. A specimen of this 

 species collected by Mr. Elschner at Fanning Island (see plate 48, fig. 2) has thicker 

 branches than Dana's type, and the branch terminals divide into rather short, 

 obtuse lobules, instead of being attenuate or having attenuate subdivisions. The 

 terminal monticules of the former are larger than those of the latter. The Fanning 

 Island specimen has the appearance of having grown in very shallow or rough water, 

 whereas Dana's type looks as if it lived either in quiet water or at a depth consider- 

 ably below low-tide-level. Except in the characters mentioned, the two specimens 

 closely resemble each other. The texture of both is dense, and the monticules on 

 the older portions of the coralla are essentially alike. 



Distribution. — Southern Philippines; Fiji Islands; Fanning Island. Not reported 

 from the Indian Ocean. 



Family MUSSIDjE Verrill. 

 Genus MUSSA Oken. 



1815. Mussa Oken, Lehrb. Naturgesch., Th. 3, Abth. I, p. 73. 



Type species: Madrepora angulosa Pallas, from Curafao. 



Oken mentions three species as belonging to his Mussa. The first is M. dianthus, 

 with which he associated Aladrepora lacera and a fossil from Swabia; the second is 

 the Madrepora angidosa of Pallas; and the third is Madrepora fastigiata, which was 

 later referred to Eusmilia by Milne Edwards and Haime. The Mussa dianthus of 

 Oken is probably Caryophyllia dianthus (Esper) M. Edw. and H. The genotype, 

 therefore, must be Mussa angulosa (Pallas), a species very abundant around Curasao. 



