TRIBE III. MADREPORACEA. 451 



16. MADREPORA TENTHS. (Dana.) 



M. cespitosa, rotun data, parce diffusa, ramulis gracillimis, vix 2'" eras- 

 sis, 3" longis, subteretibus, proliferis. Corallum caliculo apicali par- 

 vulo ('"), prominulo ; lateralibus appresso-tubiformibus, elongatis 

 (!$'") et tenuibus, margine fragilibus, extus bene striatis et scabriculis, 

 apertura orbiculatd, stettd inconspicud, duabus lamellis paulo promi- 

 nulioribus. 



Cespitose, rounded, sparingly spreading; branchlets very slender, 

 scarcely 2 lines thick, 3 inches long, subterete and proliferous. 

 Corallum with the apical calicle small ( of a line broad), a little 

 prominent; the lateral, appressed-tubiform, irregular, elongate (1 

 lines) and slender; margin fragile, exterior neatly striate and finely 

 scabrous ; aperture circular, star indistinct, two lamellse a little pro- 

 minent. 



The very slender branchlets are not evenly terete, owing to some 

 irregularity in the arrangement of the calicles, and a variation in their 

 length. The calicles are about two-thirds of a line in diameter, and 

 rather fragile; they are tubiform, and are attached, laterally, to the 

 branch, not quite to their summits; the aperture is broad and open, 

 without a distinct star. 



17. MADREPORA TUBICINARIA. (Dana.) 



M. cespitosa, suffruticosa, rotundata, ramis paulum diffusis, stride ra- 

 mosis, ramulis fere teretibus, 3-4'" crassis, vix attenuatis, apice obtusis. 

 Corallum porosum, caliculo apicali crassimo (1-1^'"), prominulo ; la- 

 teralibus appresso-tubiformibus et regularibus, f" latis et 1^-2'" lon- 

 gis, tenuibus et margine fragilibus, extus bene striatis ; apertura late 

 orbiculatd, sursum spectante, stettd breviter sex-radiata. 



Cespitose, rounded, branches but little spreading, closely ramose, 

 branchlets very nearly terete, 3 to 4 lines stout, scarcely at all taper- 

 ing, apex obtuse. Corallum quite porous ; apical calicles very stout 

 (1 to l lines broad), a little prominent; the lateral, appressed tubi- 



