184 ZOOPHYTES. 



This is a subfoliaceous species, spreading outward from a central 

 pedicel, and covered above with sinuous ridges formed of stout, 

 coarsely-toothed lamellae. Four or five of the larger lamellae cover 

 half an inch in breadth, and between these there are one to three 

 smaller lamellae. The fossae are two-thirds of an inch deep, and along 

 the bottom run two or three lamellae which unite the convoluto-porous 

 polyp-centres. The septa are thin. The specimen in the Expedition 

 collections is eight inches in diameter. 



Meandrina crispa, Lamarck, ii. 388, No. 6. 5, to which Lamarck refers as of this 



, Blainville, Man., 357. species, more probably represent the 



The figures by Seba, iii. tab. 108, No. 3 and Manicina fissa. 



13. MUSSA DIPSACEA. (Dana.} 



M. brevissime turbinata, convexa, discis breviter linearibus, fere simpli- 

 cibus. Corallum valde robustum ; cellis -f " latis, -2" ekmgatis, 

 scepe lobatis, lamellis crassioribus, tenuiter dentatis, 1'" exsertis, mino- 

 ribus alternis ; collibus interdum obsolete sukatis, septis angustissimis 

 (-!'"), solidis. 



Very short, turbinate, convex, disks short, linear, and almost simple. 

 Corallum very firm ; cells to of an inch broad, and to 2 inches 

 long, often lobed ; lamellae quite stout, slenderly and neatly dentate, 

 1 line exsert, alternately smaller ; ridges sometimes obsoletely sul- 

 cate, septa very thin ( to 1 line), solid. 



Plate 8, fig. 9, section of cell, showing outline of lamellae. 



This species has something of the habit of the crispa, but is smaller, 

 with much shorter gyri, and finer dentations to the lamellae. It differs 

 from the fragilis in its shorter and narrower gyri, its scarcely sulcate 

 ridges, and much stouter lamellae. The specimen examined be- 

 longs to the collections of the Boston Natural History Society. It is 

 about one and a quarter inches high, and two and a half in diameter. 



The Madrepora lactvca of Esper, as figured in tab. 33, (Pflanz. Fortsetz. i.), ap- 

 pears to be the above species. There is a general resemblance, although the ridges are 

 too broad and flat at top, and the cells appear too much obstructed by the lamellae. 



