POLYPE AND CORALS. 89 



tifonn cells, is quite unlike that of most other known 

 species. 



TURBINARIA DICHOTOMA Veirill, Sp. 11OV. 



Corallum large, dichotomously branched. . Branches 

 stout, subcylindrical, often flattened at the end, covered 

 with large, somewhat prominent corallites, which open 

 upward and are uniformly scattered on all sides of the 

 branches, but become crowded and unequal at the ends, 

 where many small corallites are seen among the larger 

 ones, from which they appear to rise by interstitial or 

 extramarginal budding. The lateral cells are about a 

 quarter of an inch broad, shallow, nearly circular, and 

 arranged in five or six, irregular, vertical or somewhat 

 spiral rows, those in the same row mostly from .3 to .4 

 of an inch apart, while those of adjacent rows are often 

 less than their own diameter apart. The cells are ele- 

 vated on low, broad eminences, which spread at their 

 bases and are so closely appressed to the sides of the 

 branches that the cells open obliquely upwards. Ccenen- 

 chyma roughened with papilliform and small spinous pro- 

 cesses, intermingled with others which are of various 

 irregular forms, often crest-like, or variously convoluted, 

 narrow ridges. Among the interstices of these are nu- 

 merous irregular pores, which are larger than in most other 

 species. Septa in four cycles, usually, in the larger cells, 

 with some rudiments of the fifth cycle, the number vary- 

 ing from fifty to sixty ; those of the first two cycles nearly 

 equal, about one fourth as wide as the cell, the inner 

 border perpendicular or a little concave, the summit 

 obliquely truncated, not exsert, the upper end joining the 

 margin and becoming confused with the irregular, spi- 

 nose processes of the coenenchyma, which cover the exte- 

 rior of the corallites and form the border of the cells. 

 Septa of the third cycle about one quarter narrower; 

 those of the fourth and fifth cycles very narrow and often 

 rudimentary, alternating with the wide ones of the pre- 

 ceding cycles. Columella broad, occupying about half 

 the breadth of the cells, its surface convex, formed by 



COMMUNICATIONS OF ESSEX INSTITUTE, VOL. VI. 12 OCTOBER, 1869. 



