544 PROCEEDINGS OF THE NATIONAL MUSEUM vor. 84 



The male ampullae (pi. 71, fig. 3; pi. 73) are superficial, convex, 

 with a ridged or corrugated surface. Diameter of ampulla about 0.5 

 mm; dorsal wall thin; inner surface compact. The female ampullae 

 (p. 70, fig. 3; pi. 71, figs. 1, 2, 4; pi. 72) are strongly convex, the surface 

 traversed by prominent, interrupted or continuous, often sharp ridges 

 or crests; or the surface is irregularly corrugated with occasional 

 tubercles. Diameter of ampulla 1 to 1.25 mm or about t^dce that of 

 the male ampullae; dorsal wall thicker than in male; inner surface 

 fenestrated, often with irregular branched spicules, which anastomose 

 into a wide-meshed spongy superstructure on the wall proper. 



The texture of the coenosteum of branchlets is well shown by plates 

 72 and 73. On the main branches the coenosteum is firmer, but the 

 surface is not smooth to the touch, nor is there any of the slight gloss 

 or "finish" that is found in D. sulcata. The fighter bands of the 

 vermiculation apparent in plates 72 and 73 are due in part to the more 

 porous structure of the surface layer and in part to microscopic spic- 

 ules. These are more obvious (under high magnification) on the 

 dactylotome projections and on the ridges traversing the ampullae 

 (pi. 70, fig. 3). 



Color of dried specimens: Cartridge buff (pi. 71, fig. 3), warm buff 

 (pi. 71, fig. 1), capucine buff (pi. 71, fig. 4); Ridgway's nomenclature. 



r?/;?g.— U.S.N.M. no. 43274. 



Type locality. — Station 3480, Amukta Pass, Aleutian Islands, lat. 

 52° 06' N., long. 171° 45' W., 283 fathoms, black sand, rocky. 



Specimens examined. — From the type locality, three male and three 

 female fragments (largest, the type, pi. 71, fig. 1); from station 4781, 

 one colony (pi. 71, fig. 4). 



Remarks. — I have compared specimens with examples of D. violacea 

 (Pallas) Lamarck, D. coccinea Gray, and D. nitida Verrill — color varia- 

 tions of one reef and shallow-water Indo-Pacific tropical species, D. 

 violacea. This species does not have dactylotome projections and has 

 a smooth, purple, violet, rose, red, or deep apricot corallum, D. 

 gracilis Dana (1846, p. 704, pi. 60, figs. 4, 5-56), from Tuamotu 

 Archipelago, is very small, the pale rose corallum being only 23 mm 

 high. The gastropores (0.1 mm to 0.12 mm) are one-fourth to one- 

 third the diameter of the average pores of horealis. They open in a 

 shallow sulcus, and the dactylo tomes have a slightly elevated lip. 

 The relatively broad and low female ampullae sometimes occupy the 

 entire breadth of a branch (pi. 75) and are not corrugated but are 

 covered like the rest of corallum with microscopic convexities or 

 bosses. D. rosea Kent (1871), from the east coast of Australia, is 

 probably the same species. As Dana's figure of the type is very 

 small, a photograph, enlarged five times, is given (pi. 75). Type of 

 D. gracilis Dana is Mus. Comp. Zool. no. 5507. 



