348 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



to 0.13 mm wide; vestibular arch present; peristome low with about 

 8 oral spines; only in very advanced calcification does the frontal wall 

 fuse with the peristome. The operculum has the form of the aperture, 

 yellow and well chitinized, with a broad curved sclerite extending for- 

 ward. The avicularia are comparatively minute, one on either side and 

 distant from the aperture, pointed and directed laterally, and another 

 pair of similar size and form about halfway back on the frontal, well 

 separated and directed proximally. 



The ovicell is correspondingly large, about 0.45 mm wide and long, 

 hemispherical, hyperstomial and not closed by the operculum, the texture 

 of the very thick wall similar to that of the zooecial front. 



This species is a veritable giant among the others of the genus. As 

 a rule in this genus there is only one row of areolar pores, but the nature 

 of the aperture, operculum and ovicell appear to ally this species with 

 Hippoporina. 



Type, AHF no. 69. 



Type locality, Hancock Station 438, Chatham Island, Galapagos, no 

 additional data. Also at Stations 442, James Bay, James Island; 471, 

 one-half mile north of Black Beach, Charles Island ; 452, Post Office 

 Bay, Charles Island; and 171-34, off Stephens Bay, Chatham Island, all 

 from the Galapagos at 18 to 65 fms. 



Genus HIPPOPORELLA Canu, 1917 



Hippoponella Canu and Bassler, 1920 :379, is a pure synonjmi. 



The frontal is a thick, vitreous, granulated pleurocyst with a row of 

 areolar pores. The aperture is broad proximally, slightly arcuate on the 

 proximal border and approximately as wide as the anter; the cardelles 

 strong and set well back; the vestibular arch usually delicately beaded. 

 Peristome low and thin with 2 to 4 small spines. Dietellae present. Ovi- 

 cell hyperstomial, not closed by the operculum, hemispherical, imperfor- 

 ate, often becoming completely immersed. Genotype, Lepralia hippopus 

 Smitt, 1867. 



This genus, which resembles Hippoporina in many respects, is easily 

 differentiated by the form of the aperture. 



Hippoporella gorgonensis Hastings, 1930 

 Plate 45, figs. 10-12 



Hippoporella gorgonensis Hastings, 1930 :723. 



The zoarium encrusts shells, etc., multilaminar and rough with 

 mamillate or knob-like processes. Zooecia moderate in size, the young 

 marginal ones 0.40 to 0.50 mm long by 0.25 to 0.40 mm wide, inflated 



