DIASERIS. 47 



Diaseris pusilla Pouet. 



Diasei-ls pusilla PouRT. Bull. Mus. Comp. Zobl., No. 7. 



Plate IT., figs. 6, 7, and 8. 



Corallmn subelliptical, veiy fragile. Wall flat or slightly concave, 

 imjjerforate, very thin, finely costate. Costt\3 thin, alternately large and 

 small, finely dentate. The base shows the traces of lobes joined to- 

 gether, often very imperfectly. Septa strongly dentate, laciniate, and 

 perforate, marked with strong ridges and furrows, connected with each 

 other by synapticula near the base (see Plate II., fig. 7). Five cycles 

 of septa and six unequal systems, one or two being generally 

 incomplete. The primary septa more lobed and much higher than the 

 others ; those of the lower cycles tending to unite with those of the 

 cycles preceding them. Fossa oblong, well marked. Columella rudi- 

 mentary in the shape of a narrow ridge. 



Color of the polyp dark brown, tentacles simple, conical, rather 

 long. 



Diameter of largest specimen 16 mm. 



Off" Sind Key, in 119 fathoms. 

 Off Sand Key, in 120 fathoms. 

 Off Sand Key, in 135 fathom.'!. 

 Off Alligator Reef, in 147 fathoms. 

 Off Tennessee Reef, in 174 fathoms. 

 Off Alligator Reef, in 15(j fathoms. 

 Off Alligator Reef, in 189 fathoms. 



Diaseris ctispa Pourt. 



Plate v., figs. 1 and 2. 



Corallum irregularly circular, formed of loosely joined lobes. Wall 

 very thin, horizontal, indistinctly costate, but deepl}^ furrowed in the 

 junction of the lobes. A few minute scattered spines and gran- 

 nies, particularly at the edge of the lobes. Septa subequal, not lacini- 

 ate, serrate ; the teeth equal and flattened transversely to the septa, 

 thns giving to the surface a densely ci-ispate appearance. Systems 

 unequal on account of the irregular mode of growth, four cycles and 

 seldom rudiments of a fifth. Primary and secondary septa equal, those 

 of the two next cycles slightly smaller. All the septa but those of the 

 fourth cycle reach the centre, the latter connect with the tertiaries 

 about half-way. Fossa moderately ^ concave, no columella, the wall in 

 the centre sometimes eroded. 



