448 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



Gabb and Horn also set up a new family "Phidoloporidae," the 

 description of which is worthless and misleading, but they were dealing 

 with fossil material at a period when the Reteporidae were little known. 

 Their new species P. labiata, is abundantly represented along the Pacific 

 coast in the Pleistocene of California, and its modern representative 

 (Retepora pacifica Robertson) is so similar to it that it appears to de- 

 serve no more than varietal status. 



Phidolopora pacifica (Robertson), 1908 

 Plate S3, figs. 1-2 



Retepora pacifica Robertson, 1908 :3 10. 

 Retepora pacifica, O'Donoghue, 1923 :47. 

 Phidolophora pacificOj Canu and Bassler, 1923 :154. 

 Phidolophora pacifica, O'Donoghue, 1926:72. 

 ? Retepora wallichiana Hincks, 1884:29. 



Zoarium erect, often forming convoluted masses of considerable size, 

 in which the branches are supported against each other by small columnar 

 processes (trabeculae) ; fenestrated to produce an intricate network; 

 the zooecia of a branch all face in the same direction. A very beautiful 

 specimen from off Newport Beach, California, presented by Dr. R. L. 

 BoHn, measures 110 mm long by 100 mm wide and 65 mm high. 



The zooecia vary greatly in size, usually between 0.45 and 0.55 

 mm in length, by 0.26 to 0.30 mm in width, the front nearly flat and 

 delicately granulated. The primary aperture measures about 0.09 mm 

 in either direction, the proximal border slightly arcuate with a shallow 

 median sinus, and 1 or 2 long oral spines may be present on either side. 

 The peristome soon obscures all of the primary oral features ; it rises 

 high, with a conspicuous secondary sinus (spiramen) on the proximal 

 border, the lateral edges irregular, rarely a labial pore is formed by 

 enclosing the proximal end of the sinus. 



Labial avicularia are entirely wanting; a large frontal avicularium, 

 partially erected, is present on many of the zooecia, the mandible long- 

 triangular and both rostrum and mandible hooked. A similar avicularium 

 is often present on the dorsal side, especially near the lower ends of the 

 fenestrae. 



The fenestrae are elliptical and pointed at both ends, ranging from 

 about 1.20 to 1.60 mm long and 0.50 to 0.65 mm wide. The trabeculae 

 joining adjacent fronds are round, smooth and devoid of zooecia. 



The ovicell is prominent in the young stage, smooth, subglobular, 

 about 0.20 mm wide and without a fissure; there is a small U-shaped 



