NO. 1 OSBURN : EASTERN PACIFIC BRYOZOA CHEILOSTOMATA 39 



primitive (wanting in some genera). Ooecia, when present, endozooecial 

 and embedded either in the base of the succeeding zooecium or in an 

 avicularian chamber. Levinsen, 1909:122-125, and Silen, 1941:49-54, 

 have presented the best discussions and analyses of this family and have 

 erected a number of new genera. 



Silen, 1941 :49-54, retains the old genus Carbasea Gray for species 

 with unilaminar zoaria which lack both aviacularia and ooecia. He erects 

 a new genus, Terminoflustra, for the species with squared avicularian 

 chambers, which are located at the bifurcation of zooecial rows, the geno- 

 type being Flustra barleei Busk. The genotype of Carbasea is Flustra 

 carbasea Solander. 



Genus CARBASEA Gray, 1848 ^ U.nr--P 



The zoarium is frondose with lobate branches, unilaminar. There 

 are no avicularia and no ooecia. ^ ^^-y, 



';. ^ Carbasea carbasea (Solander), 1786 -S<nnrs4. . 



Plate 3, fig. 9 



Flustra carbasea, Hincks, 1880:123. 



The zoarium is usually a broad, thin, sheet, more or less subdivided 

 into lobes, with a narrow short stalk which is attached by a narrow base. 

 There is a single layer of zooecia, all facing the same direction. The 

 zooecia are large, 0.90 to 1.25 mm long and about 0.40 mm wide, in 

 quite regular alternating series, the narrow base of one between the ex- 

 panded distal halves of those on either side ; the walls thin and the distal 

 wall strongly curved forward ; opesia occupying all of the frontal area, 

 with sometimes a slight development of a proximal cryptocyst. No spines; 

 no avicularia ; no ovicells. 



The "Lawn Sea-mat" of Ellis and Solander's Zoophytology is a com- 

 mon high-northern species in the North Atlantic and adjacent Arctic 

 Ocean. Recorded frequently from Spitzbergen south to the British Isles 

 and west to Greenland, Osburn (1932:7) extended its range to Lou- 

 byrne, Hudson Bay. It now appears in collections from Alaska and no 

 doubt is circumpolar in distribution. 



Dall Alaska Collection 3623-1670, U. S. National Museum, and 

 Albatross Collection, Cordova, Alaska, June 28, 1914, Common at Point 

 Barrow, Alaska, Arctic Research Laboratory, G. E. MacGinitie, col- 

 lector. 



