NO. 3 OSBURN : EASTERN PACIFIC BRYOZOA CYCLOSTOMATA 699 



of the autozoid tubes continued through the chamber and on above it. 

 In the broken walls of old thick zoaria the chambers appear at different 

 levels, some just beneath the surface, but others buried deeply by the 

 regeneration of the zoarium above them. There is little or no surface 

 evidence of the position of the brood-chambers, and the pustules appear 

 to have no relation to them, as shown by dissection. Borg could not be 

 certain as to the brood-chamber in his material of B. rugosa, but that 

 of his figure 2 (plate 3) appears to be similar to those of pustulosa. I 

 have observed no differentiation of ooeciostomes. 



Borgiola is certainly close to Heteropora in most of its characters, 

 but the roughened nature of the zoarial surface, the grouping of the 

 autozoids and heterozoids and the pointed processes of the taller zooecial 

 tubes separate it. 



The occurrence of this species is of unusual interest, since no member 

 of the Family Heteroporidae has hitherto been recorded from the Arctic 

 Ocean. 



Type, U. S. Nat. Mus. no. 11051. 



Type locality, Point Barrow, Alaska, Arctic Research Laboratory, 

 453 feet, encrusting a stone, G. E. MacGinitie, collector. Also on a stone 

 from 295 feet and on a shell at 60 feet. 



Division 5. Rectangulata Waters, 1887 



( Calyptrostega Borg, 1926) 



The Lichenopores 



"They fool me to the top of my bent." Shakespeare. 



"Primary zoid adherent to the substratum, never separated by any 

 joint from the pro-ancestrula ; zoarium wart-like, its basal wall adnate, 

 simple; frontal wall double consisting of gymnocyst and cryptocyst; 

 between zoids special coelomic cavities (alveoli) limited by calcareous 

 extrazoidal walls; no vestibular sphincter; brood-chamber zoarial, a 

 coelomic space corresponding to numerous alveoli, outside the fertile 

 zoid ; polypide degenerating first after having been functional for some 

 time." (Borg, 1944:211). 



The Lichenopores have always been a "thorn in the flesh" to those 

 who have attempted to work with them. Defrance established the genus 

 Lichenopora in 1823. Before this time the species were usually re- 

 ferred to Madrepora (a coral), or to Tubiilipora Lamarck. Since then 

 a large number of generic names have been proposed ; d'Orbigny was 

 especially lavish in this respect, separating out ten "genera" on trivial 



