NO. 3 OSBURN : EASTERN PACIFIC BRYOZOA — CYCLOSTOMATA 697 



them well-marked depressions; autozoids frequently forming small 

 clusters; their apertures oblique, prolonged at one side into an erect 

 pointed process; kenozoids much more numerous than the autozoids, 

 thick-walled, mostly with open apertures," Borg, 1933:331. Genotype 

 Canuella rugosa Borg, 1933 :332. 



The genus is certainly close to Heteropora and possibly may be found 

 to intergrade. However any means of separating the members of this 

 family, and especially if it is found to apply to the very numerous fossil 

 species, is welcome. 



The generic description requires modification to include an encrusting 

 species, without erect branches, B. pustulosa new species, which is de- 

 scribed below. 



Borgiola rugosa (Borg), 1933 

 Plate 76, fig. 11 



Canuella rugosa Borg, 1933:331. 



The zoarium of our single specimen measures 25 mm in height and 

 20 to 25 mm in width, rising from a broad encrusting base 20 by 10 mm 

 across, with numerous irregular branches which are sometimes bifurcate ; 

 and there is a single anastomosis. Several small subcolonies arise from 

 the lateral extension of the base. The main stem is about 5 mm in 

 diameter, the branches becoming progressively smaller until the terminal 

 ones measure 2 mm or less. Color pure white. 



The autozoids, or functional zooecia, tend to occur in small groups 

 or clusters, sometimes in radiating lines, though single autozoids are 

 also common. The peristomes usually rise slightly above the surface, 

 with the rim higher on one side and often extending into a sharp point ; 

 or the rim may be evenly rounded. The zooecial tubes are long, those in 

 the rounded branches have their origin in the center and curve outward 

 as in Heteropora; those which form the basal expansion arise on the 

 lamina and curve upward. There is a moderately broad basal lamina 

 surrounding the basal expansion. The apertures of the autozoids are 

 about 0.13 to 0.15 mm in diameter. The kenozoids are much more 

 numerous than the autozoids, always noticeably smaller but varying in 

 size, never rising above the surface and seldom entirely closed. The 

 brood-chamber has not been observed. 



A striking feature of the zoarium is the peculiar type of rugosity 

 produced by the irregular elevation of areas with increased numbers of 

 autozoids, while between these are smooth areas of lower level in which 

 there are fewer autozoids. 



