14 CATALOGUE OF MADREPORA CORALS. 



oval (sub-circular) iu outline, the longest diameter measuring about 40 

 centimeters, the shortest about 35 centimeters. The center is but 

 slightly depressed, or between 5 and 6 centimeters below the highest 

 plane of the surfiice. From this point the surface rises most rapidly 

 at first, and then forms a gentle, more or less regular, curve to the 

 margins, which are slightly below the upper plane. On all sides of the 

 center the surface is generally convex, but in some places it is slightly 

 concave.. The .shaj^e is, however, exceedingly regular for this group of 

 corals, and tlie sj)ecimeu in question is one of the most beautiful of all 

 the madrepores iu the collection. 



The pedicel is about G.i) centimeters iu diameter, and spreads very 

 slightly at its base ; its height to the {)oiut where the upper spreading 

 portion begins is only about 4 centimeters, and in the upper part the 

 interspaces between the main branches are deep and well defined. The 

 calicles extend nearly to the base in some places. 



In the thickness of the corallum, in the mode of branching, and in 

 the characters of both surfaces, this specimen agrees very well with the 

 description published by Quelch ; but the small solid areas of the lower 

 surface, caused by the coalescing of the branchlets with the branches, 

 which he mentions, are nowhere specially observable. The branchlets 

 of the upper surface are very closelj^ and regularly placed, and are^ 

 therefore, separated by narrow interspaces of very regular width. The 

 branchlets are longer, more slender, and less vertical toward the mar- 

 gin, where the structure is naturally more open than elsewhere. The 

 extreme central depressed portion is solid, with a few very small^ 

 upright branchlets and ijromiuent calicles, distributed among other 

 crowded calicles which are but slightly exsert. 



On one part of the upper surface a stout branch has started up, 

 growing obliquely to a height of 4.5 centimeters. It is closely over- 

 grown with branchlets of the same size and character as those of the 

 plane surface. 



The star of the terminal calicles is less distinct than in Quelch's fig- 

 ure, and the lateral calicles are thinner and of a looser texture than in- 

 dicated by his description. The size and shape of the calicles are, how- 

 ever, the same. While the writer cannot definitely refer this specimen 

 to Quelch's species, it certainly approaches it more closely than it does 

 any other species that has yet been described. In its general shape it 

 somewhat resembles Madrepora patella Studer,* but it differs from that 

 species in the character of the branches and calicles, the- former not 

 being obliterated on any part of the lower surface. 



12. Madrepora conigera Dana. 



Dana, Zoophytes, p. 440, pL 32, fig. 1. 

 Singapore ; U. S. Espl. Expetl., type (240). 

 Tahiti, Society Islands ; U. S. Expl. Exped. (239). 



* Monatsber. der K. Preuss. Akad. der Wissenschaften zu Berlin, 1878, p. 527, pi. 1, 

 fig. 1. 



