446 ZOOPHYTES. 



numerous rather short tubular calicles, rendering the surface quite 

 uneven. 



/3. turbinata. The corallum resembles closely the above, in its 

 smaller branchlets, both as regards their tapering form, their calicles, 

 and the proliferous extremities. But instead of spreading horizontally 

 and forming a solid or reticulate frond, the branches spread obliquely 

 upward, and are several inches in length. The specimen in the col- 

 lections is a turbinate clump, twelve inches broad at top, and the 

 same in height, and has nearly the form of an inverted cone. The 

 branches are one half to three quarters of an inch thick below ; the 

 smaller branchlets are one to two inches long, nearly a fourth of an 

 inch in diameter below, and often very proliferous at summits. The 

 upper branchlets of the margin are as regular as those of the middle 

 of the group, and the calicles not more spreading. The specimen is 

 from Tahiti. 



7- dijfusa. The branchlets are proliferous as above, and similar in 

 size and form, but the branches are one half to three quarters of an inch 

 thick, and distantly coalescent, with very large spaces ; moreover the 

 branchlets are more remote, the intervals between being often an inch. 

 A specimen belonging to the Boston Natural History Society, ap- 

 pearing to be about a fourth of a whole frond, measures eighteen 

 inches by fifteen in breadth. Though placed here as a variety of the 

 surculosa, it has more of the habit of the subulata in the character of 

 the frond, from which species it differs, however, in the length and 

 characters of its branchlets. It is probable that the surculosa assumes 

 the open character here described when it attains a large size. 



LitJwdendrum calcareum sessile? Rum- Heleropom corymbosa(1), Ehrenb., G. Ixix. 



phius, tab. 86, fig. 2 ; a reduced figure? sp. 16. 

 Mad. corymbosa, in part, Lamk. 



11. MADREPORA MILLEPORA. (Ehrenberg.} Dana. 



M. cespitosa, breviter pedicellata, lata, paulum convexa, ramis laxe re- 

 ticulatim coalitis ; infra, ramulis paucis, nudis, appressis ; supra, 

 ramulis bene teretibus, 2" longis, vix \" crassis, subsimplicibus. Co- 

 rallum ramulis obtusis, caliculis breviter labellatis, confertim imbri- 

 catis, \'" latis; stelld inconspicud, duabus lamellis valde latioribus ; 

 apicali,fere 1'" lato et %'" exserto ; ramukrum marginalium caliculis 

 valde laxioribus. 



