44 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



projecting above the succeeding zooecium; mandible elongate-triangular, 

 symmetrical, 0.30 to 0.40 mm long by 0.18 mm wide at the base, yellow 

 with a bordering sclerite, the tip much decurved and ending in a fine 

 point; attached by a pair of cardelles. 



Ovicell endozooecial, but moderately prominent, short and transverse 

 (semilunate), the surface slightly roughened, but without an umbonate 

 process. Dietellae present. No spines. 



It is apparently very similar to H. pallida (Hincks) but that species 

 is well provided with spines, both erect and curved, and the ovicells, 

 according to O'Donoghue (1926:31) are so immersed as to be invisible 

 on the surface. It is also related to H. velata Hincks but in that species 

 the avicularium is shorter and the ovicell has a different form. 



Type,AHFno. 14. 



Type locality. Albatross Station 2984 near the Guadalupe Islands oil 

 Lower California, 28°57'15''N, 118°15'45''W, at 113 fms, two colonies. 



Hincksina velata (Hincks), 1881 

 Plate 5, figs. 3 and 4 



Membranipora velata Hincks, 1881 :130. 

 Callopora triangulata O'Donoghue, 1926:35. 



The description and figure by Hincks (pi. 5, fig. 3) and that of 

 O'Donoghue (pi. 3, fig. 28) agree in practically every detail and are 

 correct with one exception. In spite of Hincks' figure and the statement 

 by O'Donoghue, the ovicell is not hyperstomial but endozooecial, as both 

 dissection and growth stages show no mural rim beneath the aperture of 

 the ovicell ; the latter is very definitely closed by the operculum, and the 

 cavity is formed by the forward extension of the upper part of the distal 

 zooecial wall. 



The figure by Hincks shows the avicularian mandible curved while 

 that by O'Donoghue represents it as straight, but both conditions may 

 occur in the same colony and it is often slightly asymmetrical, one side 

 being longer than the other. There are two very strong hinge denticles. 

 Measurements were not given, but in our material the zooecia measure 

 0.60 to 0.70 mm long by 0.35 to 0.50 mm wide, and the opesia 0.40 to 

 0.50 mm long by 0.30 to 0.35 mm wide. The ovicell is at first transverse 

 and arcuate, but assumes a triangular form by additional calcification. 

 The opesia occupies most of the frontal area ; the walls rather thick and 

 granulated ; gymnocyst present but often much reduced ; spines wanting, 

 dietellae present; avicularia vicarious. 



