454 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



This species is removed from Porella, where O'Donoghue described 

 it, because of the nature of the avicularian chamber, the vestibular arch 

 and the ovicell. The form of the primary aperture places it under 

 Lepraliella rather than Rhynchozoon, but these genera have much in 

 common. 



Recorded by O'Donoghue from a number of British Columbia local- 

 ities and from the San Juan Islands, Puget Sound. 



Hancock collections: Accession 1190, Middle Bank, Puget Sound, 

 numerous colonies. Dr. John L. Mohr, collector. 



Genus RHYNCHOZOON Hincks, 1895 



Rhynchopora Hincks, 1877 (Preoc. and renamed by Hincks). 



"Zooecia with the primary orifice transversely elliptical, lower mar- 

 gin slightly sinuated ; secondary orifice suborbicular, with a mucro on 

 the lower margin and an uncinate process immediately above it, within 

 the mouth" (Hincks 1880:385). Genotype Lepralia bispinosa Johnston, 

 1847. 



To the above characters, which are quite insufficient for the charac- 

 terization of the genus, there should be added: 1, a suboral avicularium 

 at one side of the midline and directed laterally; 2, a well developed 

 and usually strongly beaded vestibular arch ; 3, the presence of pore 

 chambers (dietellae), and 4, the nature of the ovicell, which lacks the 

 frontal fissure common to most members of the Reteporidae and has 

 instead a flat subtriangular or semicircular, lightly calcified plate above 

 the ooecial orifice. This plate, which is the exposed endozooecial wall, 

 sometimes bears a short wide labellum. 



The species are often difficult to determine, as secondary calcification, 

 which is very heavy, obscures the primary characters and these can be 

 found only on the young zooecia at the edge of the colony. It is one 

 of the genera that "try men's souls." Hincks remarks concerning 

 R. bispinosum that "This form is a difficulty in the way of the sys- 

 tematist," and Canu and Bassler (1927:32) use somewhat stronger 

 language, "La plupart des . . . especes . . . sont abominablement com- 

 pliquees par leurs ornements frontaux et leurs organes adventifs." 



Key to Species of Rhynchozoon 



1. Zooecia small and plain, a small avicularium on the rim of the 

 thin peristome, no frontal avicularia, a small lucida on each 



side of the ovicell tuberculatum 



Zooecia without these characters 2 



