72 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



Copidozoum tenuirostre (Hincks), 1880a 

 Plate 7, fig. 4 



Membranipora tenuirostris Hincks, 1880a:70; 1884:7. 

 Callopora tenuirostris, O'Donoghue, 1926:33. 

 Callopora tenuirostris, Canu and Bassler, 1929:8. 

 Copidozoum tenuirostre, Marcus, 1937:48. 



Zoarium encrusting. Zooecia of moderate size, usually between 0.45 

 and 0.55 mm in length, and 0.30 to 0.40 mm wide. Distinct, the walls 

 thick and the descending cryptocyst heavy and coarsely granulated, with- 

 out a horizontal lamina; g>'mnocyst little developed. Opesia ovate, usu- 

 ally distinctly narrowed at the operculum. Dietellae are usually present, 

 one in the distal and one or two in the lateral wall, but the pore chambers 

 may be absent leaving only large multiporous rosette plates, which ap- 

 pears to agree with the observations of Waters (1898:685) on Mediter- 

 ranean specimens. The avicularia are interzooecial, occupying the place of 

 zooecia ; the chamber usually diamond-shaped ; the rostrum long, elevated 

 toward the tip and with a narrow groove; the mandible is elongated, 

 almost filiform, with a triangular base attached to a pair of strong den- 

 ticles. Spines wanting. 



The ovicell is prominent, globose, minutely porous and decorated 

 with minute knobs or merely granulated ; not closed by the operculum. 



The original description by Hincks (1880:70) states that there is 

 "an acuminate spine at the bottom of the aperture bending inward, and 

 usually two or three on each side." Spines are entirely wanting on all of 

 the Pacific coast specimens; Waters (1898:685) found no lateral spines, 

 except occasionally a small one proximal to the ovicell in Mediterranean 

 material; and Marcus (1937:49) found no spines on specimens from 

 Brazil, though they were present, as Hincks illustrated them, in speci- 

 mens from St. Helena Island (1939:201). 



Distributed around the world in tropical and temperate waters. 

 Hincks and O'Donoghue recorded it from several localities in British 

 Columbia and Canu and Bassler from the Galapagos Islands. 



In the Hancock collections it occurred at 56 stations, distributed from 

 northern California to Peru and the Galapagos Islands, and from low 

 tide to 70 fms. 



