290 bulletin: museum of comparative zoology. 



specimens measured) dorso-ventral 1.1. Almost spheroidal posteriorly, 

 flaring at the girdle, especially in dorsal region. Epitheca low, conical or 

 dome-shaped. Girdle lists nearly equalling or exceeding girdle width in 

 height, nearly horizontal, hyaline, non-ribbed, or with numerous straight 

 riblets. Ventral fin short, little over a girdle width in height, hyaline, with 

 one secondary spine, fission spine only 2 girdle widths behind girdle. Low 

 sagittal fin, 0.2 girdle width wide, with numerous minute imperfect riblets. 

 Surface simply porulate or with small, irregular, but well defined, polygonal 

 mesh, each opening with central pore. 



Length, 150 n; dorso-ventral diameter 148 m; transverse, 165 n. 



Sta. 4734. 



Phalacroma limbata, sp. nov. 



A large species resembling P. pulchra, sp. nov. but with girdle over 0.3 of 

 total length from apex. Body almost circular in lateral view. Length 1.06 

 times dorso-ventral diameter; transdiameter 0.38 total length, greatest at 

 girdle. Outline not interrupted by girdle. Two low fins about a girdle 

 width in height, with numerous incomplete riblets along sagittal suture. 

 Ventral fin 1.75 girdle widths in height. Antapical spine 3 girdle widths 

 long, basally composed of anastomosing mesh. Girdle lists without ribs, less 

 than 1 girdle width in height. Surface pitted in center of lateral faces, areolate 

 peripherally. Pores less numerous than areoles. 



Length, excluding fin, 75 n; total, 100 ix; dorso-ventral diameter, excluding 

 fins, 68 n, total 89 m- 



Sta. 4667. 



Phalacroma porosa, sp. nov. 



A small rotund species resembling P. rotundata Clap, et Lach., but with 

 epitheca more flattened and very prominent pores. Body subcircular in 

 lateral outline, much flattened anteriorly, and often sac-like posteriorly. 

 Length 1.1 times dorso-ventral diameter, transdiameter (in individual meas- 

 ured) 0.28 dorso-ventral diameter. Epitheca not exceeding 1 girdle width 

 in height. Girdle lists equal, low, less than girdle width in height, hyaline, 

 ribbed near dorsal suture ribs. Ventral fin hyaline, increasing in height from 

 1 to 2 girdle widths posteriorly, abruptly terminating behind secondary spine 

 which is longer than the double fission spine. No sagittal fins, but well 

 developed widely displaced (in individual examined) bounding ribs in thecal 

 wall. Surface covered centrally on each side with delicate or strong tracery 

 of polygonal mesh, peripherally free from mesh. Pores large and prominent, 

 centrally located in heavier meshes, about 12 under girdle on one face, two 

 rows in girdle, and marginal row along sagittal ridges. 



Length, 51 n] dorso-ventral diameter, 43 m; transverse, 28 /x- 



Sta. 4721. 





