16 DESMOPHYLLUM. 



the costne covered with very fine sharp graniihitions. The columelLT, 

 of the recent species is also much less developed than in the fossil, 

 and the pali more slender and delicate. 



Among the varieties, those with large and prolonged primary costsB 

 (Plate II., figs. 4 and 5) appeared to present therewith good specific 

 characters, until a large specimen was found which had enlarged 

 and projecting primary costas until about half grown, and then sud- 

 denly changed to the form with equal costae. One mutilated specimen 

 has the primary costxe prolonged into horn-like appendages as long 

 as one fourth the diameter of the calicle, and surmounted with a 

 smaller prong, directed upwards. (Plate V., figs. 9 and 10.) 



The polyp of a large living specimen dredged in 115 fathoms, off 

 the Tortugas, was whitish, with brown stripes between the pali and on 

 the secondary septa. The tentacles were club-shaped, short, placed in 

 the depressions between the septa and the pali. 



On the Florida side of the channel most of the specimens were 

 immature. Until half grown the wall forms a regular cone of very 

 large aperture (about 110°) ; at a later period it becomes flatter and 

 saucer-shaped. 



One single specimen was obtained living, and was also the largest; 

 13.5 millimeters in diameter. 



Off Concli Reef, in 60 fathoms. 

 Off Alligator Reef, in 113 fathoms. 

 Off Tortugas, in 115 fathoms. 

 Off Chorrera (Cuba), in 270 fathoms. 

 Off Rebecca Channel, in 290 fathoms. 

 Off Marquesas, in 296 fathoms. 

 Off Boca Grande, in 327 fathoms. 



DESMOPHYLLUM Eiirbg. 



Desmophyllum Cailleti Duch. «fc Mich. 

 Desmophyllum Cailleti Duch. & Micri. Suppl. Mem. Coral., 1864. 



Six fine living specimens of this coral were obtained in 315 

 fathoms, off the Double-Headed Shot Keys. They agree with the 

 definition of the above species, but are more elongated and more 

 contracted at the base than the fig-ure of those authors. Wall 

 and septa are very thin and fragile, and the whole coral resembles 

 Rhizotrochiis fragilis very much. The largest specimen is 23 mil- 

 limeters in height, and 13 in diameter at the calicle. 



