356 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



Hippoporidra spiculifera (Canu and Bassler), 1930 

 Plate 55, figs. 8-10 



Hippotrema spiculifera Canu and Bassler, 1930:43. 



Zoarium encrusting and nodulous or erect with stout short branches. 

 The zooecia are cumulate, not oriented except at the margins of encrust- 

 ing colonies, more or less erected, little distinct, small, 0.25 to 0.40 

 mm long by 0.25 to 0.35 mm wide. The frontal area is ovate to 

 hexagonal, thick and porcellanous, rising slightly to the aperture which, 

 in the secondary layers often is nearly central ; one or two rows of 

 areolar pores. The aperture is slightly elongate, 0.12 mm long by 0.10 

 mm wide, straight on the sides, the small cardelles set far back and 

 the poster broadly arched the full width of the aperture. The operculum 

 has the form of the aperture, notched on the sides at the cardelles, well 

 chitinized and yellow in color, with a narrow sclerite paralleling the 

 margin. 



The full development this species presents an extravagant display 

 of oral spines and spiny frontal processes. The peristome bears six 

 tall slender spines, sometimes nearly as long as the zooecium. In the 

 position of a central umbo is a tall pointed spinous process which is 

 finely granulated to its tip, around the sides of the aperture and some- 

 times elsewhere on the frontal are other similar sharp-pointed tall 

 processes, and even on the top of the ovicell there may be one or two; 

 occasionally these processes are bifurcated near the tip. 



Small sharp-pointed avicularia are frontal in position and turned 

 in every direction. 



The ovicell is hyperstomial, prominent and smooth when young 

 with a rounded area above the orifice, but later the whole wall becomes 

 very thick and often bears a tall spine on the top. 



The species was described from Albatross Station 2813, Galapagos 

 Islands at 40 fms. 



Hancock Stations, 137-34, Clarion Island, 18°19'05"N, 114°45' 

 25"W, at 57 fms; and 1078-40, and Tepoca Bay, Sonora Mexico, 

 30°14'57''N, 112°52'27''W, at 12 fms. Also in the Galtsoff collection 

 from the Gulf of Panama, on pearl oyster shells. Also Barra Navidad, 

 Jalisco, Mexico, low tide. Dr. Yale Dawson, collector. 



