NO. 2 OSBURN: eastern pacific BRYOZOA CHEILOSTOMATA 361 



granular, with one row of small areolar pores. The aperture is elongate, 

 0.16 mm long by 0.12 or 0.13 mm wide, pyriform, the anter rounded 

 back to the strong cardelles which are directed somewhat proximally, 

 the poster is semicircular or slightly v-shaped and about two-thirds as 

 wide as the anter. The peristome is thin, slightly elevated on the sides 

 but entirely wanting proximal to the cardelles. Close behind the aperture 

 and at one side is a conspicuous avicularium with a slightly elevated 

 chamber and a long narrow rostrum directed proximally, the mandible 

 (wanting in our specimen) attached by small hinge denticles. 



The ancestrula is small in comparison, 0.30 mm long by 0.16 mm 

 wide, but is similar in most other respects to the later zooecia, even to the 

 presence of an avicularium ; the aperture diflfers in the poster which is 

 comparatively broader and shallower. 



Ovicells wanting and the chitinous structures missing from our dead 

 specimen. 



Some doubt remains as to the generic position, in the absence of the 

 ovicell and operculum, and it may prove to be a Hippoporina. The larger 

 size, thinner frontal wall and especially the nature of the avicularium 

 sufficiently distinguish it as a species from any of our species of either 

 GemeUiporella or Hippoporina. 



Type, AHF no. 74. 



Type locality, Hancock Station 1050, oflF San Miguel Island, south- 

 ern California, at 34 fms, one colony about 1 cm in width. 



Genus LACERNA Jullien, 1888 



The frontal is a pleurocyst with numerous areolar pores. The 

 aperture is rounded, the proximal border with a deep narrow sinus; a 

 narrow vestibular arch is present. Avicularia near the aperture, suboral 

 or lateral. Peristome complete, with stout oral spines. Ovicell hyper- 

 stomial, hemispherical, not closed by the operculum except in the 

 passage of eggs; perforated, the pores varying in size. Genotype, Lacerna 

 hosteensis Jullien, 1888:48. 



In young zooecia the frontal is a veined olocyst which later is 

 covered by a pleurocyst which may be either smooth or granular. The 

 sinus is always a distinct median notch which varies from square to 

 round and partially enclosed in different species. 



