NO. 1 OSBURN ; EASTERN PACIFIC BRYOZOA CHEILOSTOMATA 173 



Beania columbiana O'Donoghue, 1923 



Beania columbiana O'Donoghue, 1923:22; 1926:46 



This species has much resemblance to the widely distributed B. hirtis- 

 sima (Heller), but O'Donoghue (1926:46) points out the differences 

 as follows : much longer connecting tubules, the number and distribution 

 of the marginal spines, and in the limitation of the dorsal spines to three. 



The zoarium is a network loosely attached, the zooecia being con- 

 nected by six tubules, each nearly as long as the zooecium, to the neighbor- 

 ing zooecia. The membranous frontal area is surrounded on the sides 

 and distally by long chitinous spines, 21 to 30 in number, many of which 

 are bifurcate; on the dorsal side are three bifurcate spines regularly 

 located between the distal and lateral connecting tubules. Banks Island, 

 Cape Ebenshaw and China Hat, British Columbia (O'Donoghue). Not 

 in the Hancock collections. 



Division VI CRIBRIMORPHA Harmer, 1926 

 This Division was established by Harmer to include all of the genera 

 in which the frontal shield, or pericyst, is formed by the union of hollow 

 spines or costae, more or less fused, with pores (lacunae) between the 

 costae, the "cribrimorphs" of Lang. Opinions vary as to where in the evo- 

 lutionary series this group should be placed. Marcus (1922:47) included 

 it in the Ascophora, but has since returned it to the Anasca. Canu and 

 Bassler (1929:27-30) divided the group between the Anasca and Asco- 

 phora, and Bassler (1935:29) includes all of the cribrimorphs in his 

 Division I of the Ascophora. 



In separating this Division, Harmer discussed the possible evolution 

 of the compensation sac of the Ascophora through conditions which are 

 found in the reduction of the costal area of Figularia, which almost bridge 

 the gap between the Anasca and Ascophora. He considers that "the 

 Cribrilinidae are a transitional group, and it is thus a matter of legiti- 

 mate doubt whether they should be placed in the lower or the higher of 

 the two groups which they connect." Silen (1942:41-52) discussed the 

 formation of the ascus (compensation sac) and the calcified frontal and 

 concluded that the ascus has been evolved from the space between the 

 membraniporidan frontal membrane, which forms the floor of the sac, 

 and the inner layer of the calcified frontal wall, which forms its roof. 



Since practically all of the Cribrilinidae, the recent cribrimorphs, have 

 a broad membraniporidan frontal membrane below the pericyst (some of 

 the genus Figularia seem to be exceptions), it appears more logical to 

 retain this group in the Anasca, even though they suggest the evolution of 



