726 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



Order ECTOPROGTA 



Suborder GtENOSTOMATA 



By Raymond C. Osburn, Ph.D., D.Sc. and John D. Soule, Ph.D. 



This taxonomic report on the Pacific Coast Ctenostomata was pre- 

 pared by Dr. Soule under the immediate direction of the senior author. 

 The work was done in connection with a study of postlarval develop- 

 ment and histogenesis and the bearing of the results on the classification 

 of this group. The data on which the taxonomic changes are based will 

 be published elsewhere and bear the full approval of the senior author. 

 The new species which have appeared during the progress of the work 

 are all to be credited to the careful work of Dr. Soule. 



R. C. O. 



Sub-Order GtENOSTOMATA Busk, 1852 



The chitinous zoaria may be incrusting, erect, stolonate or burrowing. 

 The zooecial aperture is essentially simple, being closed by the inversion 

 of the tentacle sheath on retraction of the polypide. In some genera spe- 

 cialized apertures are present, including those that are bilabiate, pro- 

 duced or even operculate. The operculum present in one genus of 

 burrowing ctenostomes is analogous to the opercula of the cheilostomes. 

 No avicularia or true external ovicells are present, although specialized 

 gonozoids do occur. Kenozooecia, modified as stolons, are present in the 

 stolonate groups, or as spines in the carnose forms. 



Division 1. Garnosa Gray, 1841 



Ctenostomata that have in common a comparatively heavy non- 

 calcareous cuticle, giving the zoaria a fleshy or leathery appearance. The 

 colonies included within this group are usually incrusting, but they may 

 rise in thin flabellate or palmate fronds, sac-like expansions, or they may 

 be cylindrical or pedunculate structures. 



Key to the Families of the Division Carnosa 



1. Zoaria primarily incrusting 2 



Zoaria erect, clavate, with kenozooecial peduncle . . Clavoporidae 



2. Zooecia with aperture closed by simple folds . . . Alcyonidiidae 

 Zooecia with modified apertures 3 



3. Aperture bilabiate, zooecia with kenozooecial spines . Flustrelltdae 

 Aperture raised, quadrangular, zooecia with 



multiporous septulae Pherusellidae 



