ART. 13 BEYOZOAN FAUNA CANU AND BASSLER 19 



their state of preservation does not permit us to make a serious 

 study. 



All of the synonymies given for this species aie false. The de- 

 terminations made without illustration must be revised, and there is 

 confusion between many species. 



Biology. — Our specimens were in reproduction and fixation in 

 April, 1888. In the Gulf of Mexico we have observed it in March 

 and Aj)ril, 1885. It is essentially a tropical species. 



Geographic distrihution. — Atlantic: Brazil, 27 fathoms; Gulf of 

 Mexico; Habana, 201 fathoms; between Cuba and Yucatan, 24 

 fathoms ; Florida, 30-133 fathoms ; Fovey, 40 fathoms. 



Geologic cUstrihutioii. — Pleistocene of Panama. 



Occurrence. — Galapagos Islands, D. 2813 and D. 2815. 



Cat. Nos. 8489, 8490, U.S.N.M. 



Genus HIPPOMENELLA Canu and Bassler, 1917 



HIPPOMENELLA PARVICAPITATA, new species 



Plate 2, Figures 7-11 



Description.. — The zoarium incrusts the debris of shells and echi- 

 noids. The zooecia are distinct, separated by a deep furrow, some- 

 what elongated, elliptical or rectangular 

 on the margins. The frontal is convex 

 and formed by a pleurocyst surrounded 

 by a triple row of areolar pores. The 

 apertura, visible at the bottom of the ^ 

 peristome, is semielliptical. The peris- figure 3.— hippomenella parvi- 

 tomice bears two very small cardelles capitata, new species, a-c, 



'' DIFFERENT FORMS OF OPERCDLA, 



separating a very large anter from a x 85 

 very small concave poster. The ordi- 

 nary zooecia bear a small triangular avicularium, adjacent to the 

 peristome, transverse, the point oriented exteriorily. The marginal 

 zooecia very much enlarged, bear two avicularia arranged sym- 

 metrically. The ovicell is small, very globular, marginated, and 

 finely porous. 

 Measurements. — 



fAa= 0.14-0.16 mm. [Zs= 0.60-0.70 mm. 



Aperturaj^^^OjL^Qlgj^jn. Zooecium|^^_0 40_()50j^^j^ 



Variations. — The zooecia are arranged in linear series branching 

 dichotomously rather regularly, so that their size increases without 

 ceasing from the center to the circumference. Our measurements 

 relate to the cells placed at a distance from the border. The mar- 

 ginal cells are rectangular and considerably enlarged. The ances- 

 trula is very small, of the ordinary form but deprived of avicularia. 



