514 PROCEEDINGS OF THE NATIONAL MUSEUM VOL.84 



La Plata. In Moseley's species there are 12 to 16 dactylo tomes, 

 while the gastrostyle is much slenderer and shorter than in moseleyana . 

 According to Moseley's figure (Moselej^, 1879, pi. 39; also pi. 35, fig. 

 13) the style in length equals about one-fifth the depth of the gastro- 

 pore. In 'profunda the ampullae are much smaller and "are usually 

 entirely sunk beneath the surface, but somethnes near enough to it in 

 situation to raise upon it very small conical elevations, which easily 

 escape notice, and are present only here and there. The am.pullae 

 are present in abundance in the walls of the pore systems and at their 

 bases." 

 This species is named in memory of H. N. Moseley. 



ALLOPORA MOSELEYANA foma LEPTOSTYLA. new 



Plate 52 



Diagnosis. — Differing from A. moseleyana in having a distinctly 

 slenderer gastrostyle, which does not crowd the style chamber, and 

 in having male ampullae, which form smaller superficial blisters. 



Description. — There are two fragments of large branches, which 

 indicate that this form grows to a considerable size. The type 

 (pi. 52, fig. 2) is apparently a young colony. 



The form of the cyclosystems does not differ materially from that 

 of moseleyana. Dactylopores 7 to 12; dactylo tomes radially as in 

 moseleyana; gastrostome often slightly constricted. Gastropore 

 averages a little shallower than in forma moseleyana. Style chamber 

 well differentiated. The gastrostyle is about 0.5 mm long, slender, 

 cylindrical-lanceolate in lateral profile. Diameter of cyclosystems 

 0.75 to 0.95 mm; depth of gastropore 1 to 1.2 mm. On each of two 

 truncated branch-ends caused by fracture, t\\'0 cyclosystems have 

 regenerated. 



Male ampullae (pi, 52, fig. 1) small, fomiing low conical protuber- 

 ances, the width of which is less than that of cavity of am.pulla (0.5 

 mm). Interior wall as in moseleyana. Fem.ale ampullae like those 

 of moseleyana (pi. 52, fig. 3). 



Color of dried colony very pale buff, bleaching to white in sodium 

 hypochlorite solution. 



Typs.—U.S.IS^.M. no. 43270. 



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

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



Specimens examined. — From type locality: Type and parts of 2 

 other male colonies; 4 fragments of at least 2 female colonies. 



Remarks. — This fonn appeai-s to be a variant of moseleijana, as 

 indicated. When the extraordinary number of species and sub- 

 species dredged at station 3480 is taken into consideration, tlie question 

 of hybridism is sure to arise; but there is absolutely no information 

 upon which to base an answer. 



