446 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



siderably in size and elevation and sometimes directed partially out- 

 ward) ; 2, this form is sometimes replaced by a short-spatulate avicu- 

 larium which is little or not at all elevated and is usually much reduced 

 in size, and similar small avicularia sometimes occur laterally and are 

 variously oriented. Both kinds are present on the dorsal side, but the 

 small spatulate ones are much more numerous. The kenozooecia of the 

 dorsal side also usually have 1 or more pores, especially the lateral ones. 



The ovicell is characteristic of the genus, pyriform with a median 

 elongate fissure which remains open, a narrow U-shaped labellum with- 

 out a keel and narrow lateral flanges which extend beyond the labellum. 



This species resembles R. denticulata (Busk) in many of its char- 

 acters but is distinguished from it by the absence of labial avicularia, 

 the absence of bicuspid avicularia, the absence of the toothed fenestral 

 avicularium, the larger number of frontal pores and the nature of the 

 adult peristome. 



Type, AHF no. 96. 



Type locality, Hancock Station 275, Raza Island, Gulf of California, 

 28°48'00"N, 113°00'00"W, two complete colonies and several frag- 

 ments, 40 fms. Also at 2180, two miles east of Magdalena Bay, Lower 

 California, 18 fms, several complete colonies and fragments; and two 

 fragments from U. S. National Museum No. 1474. 



Reteporellina denticulata var. gracilis new van 



Plate 53, figs. 8-10 



Retepora denticulata Busk 1884:109. 



Reteporellina denticulata^ Harmer, 1934:581 (bibliography). 



Zoarium erect, ramose, irregularly dichotomous, no fusion of 

 branches in our specimens; branches slender, width 0.65 to 0.80 mm. 

 Zooecia usually in 3 alternating series, about 0.50 mm long by 0.30 

 mm wide, the younger zooecia separated by distinct ridges, the frontal 

 surface flat and granular, the peristomes tubular and sharply elevated ; 

 the frontal pores very regularly 2 (occasionally 1 or 3). The peristome 

 is infundibuliform, the labial pore enclosed and the sides of the peristome 

 rise a little higher than the proximal and distal borders and are provided 

 with small denticles, usually 2 on the inner border and 3 or 4 on the 

 outer, but there is much variation. 



Large bifurcate labial avicularia are rare and are almost exactly like 

 those in Harmer's figure (1934: text fig. 33). The frontal avicularia 

 are usually small, oval or short-spatulate and variously oriented, only 

 rarely is there a larger, more elevated one. On the dorsal side the avi- 



