534 PROCEEDINGS OF THE NATIONAL MUSEUM vol.84 



sionally oval orifice with small accessory perforations. The margin 

 of the orifice is usually entire but may be irregular or even deeply 

 indented. Diameter of larger cyclosystems 2 to 3 mm; of the smaller 

 about 1.5 mm ; depth variable, usually less than extreme width of cyclo- 

 system but more than half that width — around three-fifths to four- 

 fifths of the width. 



In an alcoholic specimen the prominent tentacular dactylozooids 

 are bent over the retracted gastrozooid. These dactylozooids emerge 

 from the dactylotome at a considerable distance below the margin of 

 cyclosystem (fig. 5d) not nearly even with margin as figured by 

 Moseley for C. moseleyi (1879, pi. 42). 



The ampullae of both sexes are lodged in the swollen lid and its 

 stem. In the male type colony there are upward of 11 (fig. 1). I 

 have found as few as 5. In the rather small hd, marked a in figure 7, 

 there were six ampullae, of which three were in the lid proper and 

 three in the vertical portion. The swelling which indicates these 

 stem ampullae is shown in figures 4 and 6. In the bottom of each 

 ampulla (fig. 1) is a small natural aperture. Figure 3 shows a ver- 

 tical section of a cyclosystem in which the hd has attachments on 

 opposite sides as in figure 2. 



There are two fragments of a female colony 50 by 40 mm and 45 

 by 30 mm. The large ampulla occupies the lid and stem, the size 

 varying with the maturity of contents. Several ampullae examined 

 contained a mature planula similar to that figured by Moseley (1879, 

 pi. 42), its ectoderm crowded with elongate nematocysts. After the 

 escape of the planulae the remains of the lid are absorbed or else 

 sloughed off. It then regenerates from the base of stem. This is 

 indicated by the number of cyclosystems with budding or partly 

 developed lids. The ampulla originates in the bend of the stem. As 

 the lid grows it enlarges, or more correctly, perhaps, the development 

 of the embryos occasions the extension of the ampulla and hence the 

 growth of the lid. The amipulla extends only a short distance into 

 coenosteum at base of stem. 



Thickly sprinkled all over the coenosteum are small shallow pits 

 0.07 to 0.11 mm in diameter, the nematophore pits. There is usually 

 a fairly definite row of them on the margin of the lids. They are less 

 conspicuous than in figure 7. The surface of the coenosteum under 

 low magnification is smooth, but mider high shows fine low anastomos- 

 ing ridges, 0.05 to 0.08 mm in diameter. 



Color of dried colony, yellowish white, which bleaches to pure white 

 in sodium hypochlorite solution. 



Type.— U.S. ISIM. no. 42876. 



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

 52°06' :N., long. 171°45' W., 283 fathoms, black sand and rocks; 

 bottom temperature not recorded. 



