74 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



bifid; one more proximally on each side, alcicorn with 3 to 6 points, 

 recumbent over the opesia; in advanced stages the points may fuse, as 

 stated by O'Donoghue. The avicularia are interzooecial, with a very 

 elongate narrow rostum, and the mandible is similarly long (as much as 

 0.40 mm) and attenuated or filiform. Dietellae present. 



Ovicell rather large, averaging 0.20 mm wide, prominent, the surface 

 delicately granulated. 



O'Donoghue placed this species "provisionally" under Amphible- 

 strum, but the opesia occupies all of the frontal areaj there is no hori- 

 zontal cryptocyst, and the avicularia are vicarious. 



Described by Hincks from British Columbia and recorded by O'Dono- 

 ghue from numerous localities from Victoria and the San Juan Islands 

 northward. 



Hancock Stations: Distributed along the whole western coast of the 

 United States and south along the peninsula of Lower California, and in 

 the Gulf of California. 



Copidozoum spinatum new species 

 Plate 7, fig. 3 



The only colony completely encrusts a rounded object. The zooecia 

 are of moderate size, 0.45 to 0.55 mm long by 0.26 to 0.30 mm wide; 

 distinct and the mural rims never in contact ; opesia elliptical ; mural rim 

 thin and the cryptocyst very narrow and scarcely granulated. The rim 

 is beset with numerous spines of equal size, 5 to 7 on each side. The 

 interzooecial avicularia are small, the rostrum short (0.13 mm), but 

 otherwise similar to those of tenuirostre. Multiporous septulae. 



Ovicell globular and very prominent, about 0.18 mm wide; perfor- 

 ated with minute pores and delicately granulated. The pores are defi- 

 nitely larger than in tenuirostre where they are usually visible only by 

 transmitted light in balsam mounts. 



The zooecia have much the appearance of C. (Membranipora) plan- 

 um, as shown in Hincks' plate 11, fig. 2 (1880), but they are much 

 smaller and the array of marginal spines is an important difference. 

 Apparently all of the spines are simple and of about the same size, judg- 

 ing by the bases ; the specimen was dead and only the bases of the spines 

 remain. 



Type,AHFno. 18. 



Type locality, Hancock Station 339, Gulf of Dulce, Costa Rica, 

 8°24'20''N, 83°13'40''W, 48 fms. One colony. 



