100 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 16 



Bank, 45-46 fms; Middle Bay, Cape Arago State Park, Coos Co., Ore- 

 gon, intertidal; Horseshoe Cove, 2 mi north of Bodega Head, Sonoma 

 Co., Calif., shore; Santa Barbara Basin, 321 fms; Salmon Point, Men- 

 docino Co., Calif., shore; Point Arena Reef, Mendocino Co., Calif., 

 shore. 



Balanophyllia osburni Durham and Barnard, new species 



Plate 15, figs. 63a-d 



Corallum of moderate size, ceratoid, attached by a small base ; calice 

 slightly oval in cross-section, fossa moderately deep, wall highly perfor- 

 ate ; septa in 4 cycles, in typical balanophylloid pattern, septal interspaces 

 2-3 times as wide as thickness of primary septa; septa of first and second 

 cycles slightly exsert, remaining cycles less so ; first and second cycle septa 

 sharply rounded at top and descending obliquely into bottom of fossa; 

 inner edges of first and second cycle septa smooth, inner edges of third 

 cycle slightly crenulate, with inner margins of third and fourth cycle 

 septa highly dentate above their junction; first and second cycle septa 

 slightly perforate, remaining cycles more abundantly so; septal faces 

 with moderately abundant and prominent granules ; costae correspond- 

 ing to septa, those of first and second cycles slightly more prominent 

 than the remainder, ornamented with numerous prominent, spinose 

 granules; costal interspaces about one-half the width of costae, moder- 

 ately deep; columella small, rounded, rising slightly above the floor of 

 the calice. 



Remarks: This species resembles Balanophyllia cornu Moseley, but 

 the columella is not as prominent as in that species, no septa of the fifth 

 cycle are present, and perforate septa are present in contrast to the imper- 

 forate septa of B. cornu. This species does not closely resemble any other 

 described Eastern Pacific form. 



It is distinguished from B. galapagensis Vaughan by the deeper fossa, 

 the smaller columella, the thinner septa and the smaller septal granules. 



Several specimens from Bottom sample 427 (the Galapagos Islands) 

 may represent the young of this species. They have a complete third 

 cycle of septa and some of the fourth present; the calice is deep and the 

 columella is very small. 



Dimensions of holotype: Height 19 mm, calice 7 by 8 mm, depth 

 of calice 3 mm. 



Holotype: AHF no. 23, with one paratype. 



Type locality: Bottom sample 450, south of Indefatigable Island, 

 Galapagos, 60 fms. 



