512 PROCEEDINGS OF THE NATIONAL MUSEUM vor.. 84 



ALLOPORA MOSELEYANA, new species 



Plate 49, Figure 2; Plate 50; Plate 51; Plate 53, Figxtres 1-16 



Diagnosis. — Colony large, flabelliform, concavo-convex, grayish 

 white with strongly differentiated stems and branches, both often 

 anastomosing in mature colonies; cyclosystems prominent, with 7 to 

 12, general^ 9 or 10, dactylopores and a fairly deep, usually straight 

 gastropore; gastrostyle robust, pointed; cyclosystems very scarce on 

 posterior face of colony; surface of coenosteum very compact, hard, 

 lustrous. 



Description. — Colony large, flabelliform, concavo-convex, with 

 massive main branches, some of which anastomosing; branclilets veiy 

 irre^ilar, flattened, and springing from sides of the principal stems; 

 only a few from concave front of colony and occasionally a short 

 abortive twig from the back. Length of type (only a part of a larger 

 colony) 190 mm; width 160 mm. 



The cyclos}/ stems are normally protuberant from one-fourth to 

 about their own diameter. On the lateral face of branclilets, wliich 

 are close to other branchlets, the cyclosystems are usually flush with 

 the surface, a very neat adaptation to the necessities of their situation. 

 Dactylotomes 7 to 12, usually 9 or 10, with subparallel sides, the radial 

 dimension commonly about one-fourth total diameter of system. The 

 spiculate dactylostjde extends slightly above mouth of pore as seen 

 from side of gastropore. Gastropore rather deep, with a v/ell-defined 

 ventral chamber, the upper margin of which is spiculate and surrounds 

 the style at about midheight. Depth of gastropore two and one-half 

 to three times length of style. Gastrostyle robust, spiculate, 0.45 to 

 0.6 mm in length and 0.25 to 0.3 mm in diameter. As viewed from 

 above the style occupies a conspicuous portion of the width of the 

 gastropore, especially in those cyclosystems on the exposed front of 

 the colony. The style shown in plate 53, figure 1, is of minimum 

 width. Diameter of c3^closystem 0.85 to 0.9 mm; depth 1.2 to 1.7 mm. 



Male ampuUae superficial, numerous on back of the brancidets (but 

 not main branches) and also on front (pi. 51; pi. 53, figs. 1 and 16, a). 

 They form circular, abruptly convex swellings (a little less than the 

 diameter of a cyclosystem), wliich are usually provided with an apical 

 differentiated protuberance (often perforated) and sometimes carry 

 also accessory, often smaller, protuberances evidently the same as 

 those scattered on surface of coenosteum. Cavit}^ of ampulla sub- 

 spherical, its inner surface deeply fenestrated and with irregular thin 

 protruding laminae and flattened chisel-shaped spicules. There 

 appear to be a few deeper-lying ampullae. Female ampullae (pi. 49, 

 fig. 2; pi. 50) larger, low hemispherical, with a smooth outer surface. 

 Surface of cavity not so rough as in male. 



