NO. 1 OSB URN : EASTERN PACIFIC BRYOZO A CHEILOSTOMATA 139 



are all normal in form with a triangular mandible, the lateral avicularia 

 very small and median ones somewhat larger, slightly elevated and ori- 

 ented laterally. Three spines are usually present, two (or three) outer 

 and one inner, the first outer and inner ones sometimes sinuous and di- 

 rected across above the aperture. The scutum is large, oval, covering 

 most of the opesia, with a well-developed alcicorn area, the proximal lobe 

 larger and the distal lobe slightly elevated above the operculum. 



The vibracular chamber is small, about one-third the length of the 

 zooecium, the groove longitudinal and somewhat on the inner side; the 

 seta is small and about as long as the zooecia. The small radicle chamber 

 is at the outer side of the proximal end of the vibracular chamber; radicle 

 smooth, without hooks (diameter 0.05 mm). 



The ooecium is very large and conspicuous (0.25 mm or more in 

 length by about 0.20 mm in width), somewhat depressed and not elevated 

 at its distal extremity; it extends to the opesia of the distal zooecium ; the 

 non-tubular pores are about twice as large as is usual in the genus. 



Type, AHF no. 33. 



Type locality, Hancock Station 1263-41, 1^ miles off north end of 

 Cedros Island, Mexico, 45 to 55 fms, several branches without base. 

 Also Station 1162-40, eleven miles south of Seal Beach, California, 82 

 fms, on sponge. 



Scrupocellaria mexicana new species 

 Plates 18, figs, 1 and 2, and 21, fig. 3 



Zoarium rather small and spreading; internodes of moderate length, 

 1 to 1.5 mm, averaging about 0.40 mm in width, joints yellow, crossing 

 the proximal part of the opesia of the outer zooecium. 



Zooecia small, short (0.26 to 0.30 mm long by 0.20 mm in width 

 at the widest part), closely set, a little narrowed below the opesia which 

 occupies about two-thirds of the frontal length. Opesia ellipsoid, a little 

 narrowed proximally, the cryptocyst narrow and smooth. Scutum rounded, 

 the basal corners slightly produced, not quite covering the opesia, alcicorn 

 pattern well developed. Spines usually three outer and two inner, all 

 small but the second and third outer spines somewhat enlarged ; none of 

 these are forked. 



Frontal avicularia on nearly every zooecium, slightly elevated with 

 a triangular mandible directed diagonally outward and downward. The 

 avicularium of the axillary zooecium is of the same pattern, but some- 

 what higher and larger. The lateral avicularia are small and sometimes 

 wanting. The vibracular chamber, on every zooecium, is small and not 



