518 VerHll, JVutes on Radlata. 



lai-ly scattered over the whole surface, mostly at distances varying 

 from -02 to -10 of an inch. The principal septa vary from 6 to 10, 

 but are mostly 7 or 8, quite narrow at top, but much thickened, 

 broader and united well together below, so as to form a cup-shaped 

 aperture to the cell, around and above the small deep central pit, and 

 entirely separating the very small interseptal sjiaces, in which the 

 minute, round, projecting points of the small septa may be easily dis- 

 tinguished. Central cavity broader in its upper part than in the pre. 

 ceding species, but with the central pit smaller, nearly filled by the 

 small, round, conical columella. Color light red, the branches often 

 yellowish at tips. 



Ncah Bay, Washington Territory, — Collection Museum of Compar- 

 ative Zoology. 



Although this species resembles the preceding in color and mode of 

 growth, it is quite distinct in the form and structure of the cells. In 

 this they are raised, circular, regular, and cup-shaped, while in the 

 preceding they are stellate, often irregular, not cup-shaped, with larger 

 and fewer septa, the border is scarcely raised, and the columella is 

 larger. 



Family, Pocilliporid.e Verrill. 



Synopsis Polyps and Corals of N. Pacif. Expl. Exp., Part iv, p. 56, in Proceedings 



(Communications) of Essex Institute, vol. vi, p. 90, 1869. 

 FavositincB {pars) Dana, Zooph., p. 514, 1846. 

 Pocilloporince (subfamily of Favositidce) Edw. and Haime, CoralL, iii, p. 301, I860. 



Corallum with an encrusting base at first, from which arise clusters 

 of lobes or branches, which grow by interstitially budding at the ends. 

 Coenenchyma abundant and very compact on the sides of the branches 

 and base, but almost entirely wanting among the crowded terminal 

 cells. Cells small, angular or circular, often filled up below with a 

 solid deposit; the transverse plates generally extend entirely across 

 the cells below. Septa 6 to 24, generally twelve, often rudimentary. 



The descriptions and drawings of the polyps of Pocillipora by Mr. 

 Bradley, show conclusively that the genus is a true madreporian, as 

 we have already mentioned in other articles.* It seems also to be 

 most closely allied to Oculina and Stylophora, both in the structure of 

 the polyps and coral. Its aifinities with the numerous extinct genera 

 having the same tabulate structure is a subject requiring a great 

 amount of careful investigation. From the Favositidce, as a whole, 

 it difters in having an abundant coenenchyma. Favosites differs also 

 in having perforate walls, and doubtless ought to be separated, at least 



* On the Affinities of the Tabulate Corals, in Proceedings of the American Associa- 

 tion fir Advancement of Science, 1867, p. 148. See also Proc. Essex Inst., vi, p. 90, 1869. 



