TRIBE I. ASTR^EACEA. 197 



cles grayish-green; tentacles minute. Corallum with the foliaceous 

 septa less thin and large than in the lactuca, about 2 inches high ; 

 cells usually 1 inch broad, very rarely with lateral oririrnes; lamella? 

 numerous, and not becoming obsolete at the margin above, some- 

 what granulous ; under surface with more crowded stria3 than in 



the lactuca. 



i 



Plate 9, fig. 11, natural size; 11 a, section of corallum, with outline 

 of lamellae. 



The Feejee Islands. Exp. Exp. 



This species resembles the preceding, but is smaller, and the crests 

 stouter and less deeply laciniate-lobed, with the striating lamella? con- 

 tinued to the top edge, and not becoming obsolete. There are seldom 

 if ever any lateral polyps to the folia, and the under surface of the 

 corallum is more closely striated. The only specimen collected was 

 a small convex clump, four inches broad and three high. Seba's 

 figure, referred to under the lactuca, is near this species, and if not 

 taken from a much worn specimen of the former, may be identical 

 with it. 



GENUS VI. CAULASTRjEA. DANA. 



Astr&idcz segregato-gemmatoe, cespitosce; caulibus polypisque subcylindri- 

 cis. Corolla fragilia, extus striata, inter dum denticulata; celld sub- 

 orbiculatd, late excavatd ; lamellis incequaliter exsertis, subintegris, 

 valde numerosis. 



Segregato-gemmate, cespitose, with the stems and calicles subcylin- 

 drical. Coralla fragile, exterior striate, sometimes denticulate ; cell 

 nearly orbicular, broadly excavate ; lamella? unequally exsert, sub- 

 entire, very numerous. 



The corals of this genus grow in broad convex cespitose clumps, 

 seldom regularly hemispherical like the Mussa?. Though near them 

 in many characters, they are much smaller (about half an inch in 

 diameter), more cylindrical, and have thin and nearly entire lamella? 



50 



