NO. 2 OSBURN: eastern pacific BRYOZOA CHEILOSTOMATA 321 



of pores but these are merely the bottoms of the grooves at the edge of 

 the secondary cover. It is almost exactly like that of Stephanosella bia- 

 perta, but is smaller and less embedded. 



The "special pores" of the fossil in original description are the lateral- 

 oral avicularia, the mandibles of which vary from round to triangular. 

 The frontal avicularia, sometimes wanting but often abundant, are 

 moderately large, the chamber elevated and often covering most of the 

 frontal proximal to the aperture, the mandible triangular and acuminate. 



This species has been confused with Stephanosella biaperta on the 

 Pacific coast to such an extent that the synonymy is much in doubt, except 

 where authors have indicated the nature of the frontal. It is possible that 

 the tremocystal species of the Atlantic and Mediterranean which has 

 been confused with S. biaperta, may also be cornuta, but there are slight 

 differences in the aperture and in the position of the lateral-oral avicularia. 



The species was described from "Santa Barbara, California. Mio- 

 cene," but a terminal footnote to the work makes the correction that the 

 stratum should be "Post-Pliocene." It is now known to be Pleistocene. 

 The records of Hincks and of O'Donoghue of S. biaperta for British 

 Columbia are probably of this species, and certainly the record by Robert- 

 son from southern California belongs here. Also those with a perforated 

 frontal listed by Canu and Bassler from the Pleistocene of California 

 and from the Galapagos Islands are evidently S. cornuta, and Canu and 

 Bassler (1923:100) suggested separating them as var. cornuta. 



It is an abundant species all along the coast and neighboring islands 

 from southern Alaska to the Galapagos Islands and from near shore to 

 a depth of over 100 fms; recorded at 124 Hancock dredging statious. 



Schizoporella dissimilis new species 

 Plate 37, figs. 12-13 



Zoarium encrusting, multilaminate (one colony shows 7 layers), the 

 surfaces of older zoaria somewhat rough. Zooecia of moderate size, 0.40 

 to 0.50 mm long by 0.25 to 0.35 mm wide, roughly hexagonal and ar- 

 ranged in quincunx, distinct with deep grooves and moderately inflated 

 in the younger stages. The frontal is a tremocyst with numerous funnel- 

 shaped pores, smooth when young, covered by a thick shining ectocyst 

 which in older zooecia obscures both pores and granulation. The aperture 

 is transversely ellipsoid, 0.13 mm wide by 0.10 to 0.12 mm long, with 

 a broad and moderately deep sinus, the cardelles small. Peristome thin 

 and low, later obscured by the encroachment of the thick frontal; the 

 secondary peristome is low and thick, often wanting, no spines. The 



