234 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 105 



Measurements of the external, visible frontal surface of nonfertile 

 zooecia are: length from 0.677 to 0.936 mm. (average 0.788 mm.); 

 width 0.288 to 0.461 mm. (average 0.366 mm.). Measurements for 

 actual zooecial length are much greater (0.864 to 1.44 mm., average 

 1.076 mm.) because so much of the proximal part of a zooecium is 

 hidden beneath and between the side-front walls of neighboring 

 zooecia. Zooecial walls are of crystal clarity, smooth and shiny 

 (pi. 5, A). Zooecial outlines are sometimes marked by a sizable 

 salient razor- thin lamella (w in pi. 5, A) which looks like a glass parti- 

 tion. Occasional twigs may have a few tiny tubercles or bumps, 

 very far apart. Cryptocyst ridges are nearly straight, thin, barely 

 noticeable in this species. They are shown in plate 4,1 in nearly all 

 zooecia. They converge proximaUy but they do not meet. There 

 also occur delicate, short, inconspicuous parentheses around the 

 zooecial orifice (pi. 4,C,H). These are called chitinous rods by Busk. 



Zooecial orifice: The orifice is set very close to the distal arch 

 of the zoid wall and its dimensions are: length from 0.086 to 0.115 mm, 

 (average 0.098 mm.); width 0.144 to 0.173 mm. (average 0.163 mm.). 

 It is hemispherical; its proximal border is very faintly concave (pi. 

 4,C). There are two small conical condyles, one at each proximal 

 corner. A small shallow sinus also is at each corner. An operculum 

 fits very snugly into the orifice and its outline is the same as that of 

 the orifice (pr in pi. 4,H; pi. 5,B-D). The operculum is smooth and 

 nearly flat on the external side. From its hemispherical rim a broad 

 flange extends inward (f in pi. 5,D). To the two lateral sides of the 

 flange are attached two calcified scapula-shaped plates containing 

 fiber bundles, giving the operculum the appearance of a drawbridge 

 (pi. 5,B, and mp in pi. 5,D). 



OviCELLs: The oviceUs are endotoichal, with truncated ends and 

 gently curving sides, giving them a somewhat rectangular appearance 

 (ov in pis. 4, J and 5,A). Their dimensions are: length from 0.259 to 

 0.360 mm. (average 0.310 mm.); width 0.230 to 0.288 mm. (average 

 0.261 mm.). The oviceU opens to the outside by an elliptical 

 ooeciopore (op in pi. 4,J), which is from 0.043 to 0.065 mm. (average 

 0.054 mm.) long and from 0.058 to 0.115 mm. (average 0.096 mm.) 

 wide. The ooeciopore is located very close to the distal lip of the 

 zooecial orifice, much closer than in Cellaria moniliorata. The side 

 and frontal walls of the three neighboring zoids cover the frontal 

 surface of the ovicell, meeting in a salient X suture on the ovicell 

 (pl. 4,J). 



Avicularia: The avicularia (pl. 4,A,B,E) are vicarious, about 

 the size of the autozoids. They are from 0.734 to 0.922 mm. (average 



