of the British Jurassic Bryozoa. 201 



Diagnosis. — Zoarium dendroid, erect, growing in thick, 

 solid brandies, wliicli anastomose occasionally. Tiie branches 

 are regularly cylindrical, or compressed (form dumetosa) . The 

 surface is level, or raised into pustules (var. pustulata) . 



Zooecia thin-walled ; diaphragms numerous. Aborted 

 zooecia scattered irregularly through the zoarium. 



Distribution. — England : Great Oolite and Cornbrash. 

 Foreign : Bathouian, France. 



2. Ceriocava laxata, sp. n. 



Diagnosis. — Zoarium with branches fairly regularly cylin- 

 drical. 



Peristomes irregular in shape, size, and arrangement. 

 Number of zooecia in a branch comparatively limited. The 

 central axis consists of few zooecia, irregularly and loosely 

 arranged. 



Distribution. — Inferior Oolite, Leckhampton. 



Affinities. — This species is most nearly allied to Ceriocava 

 corymbosa (Lamx.). The differences can be clearly seen in a 

 longitudinal section. The central axis has far fewer zooecia, 

 and these are not so tightly packed. It is not easy to 

 separate the specimens of the two species by the external 

 characters ; but the apertures in G. corymbosa are more regular 

 than in G. laxata. 



Synopsis of Species q/'Entalophoridas. 



A. Zooecia long and tubular ; apertures equal in dia- 



meter to zocBcia. 



I. Branclies slender ; structure simple. 



a. Apertures never in linear series. = Entalophora. 



a. Zoarium of long thin cylindrical branches : 



(1) free distal end long E. cellarioides. 



(2) free distal end short E. magnipora. 



b. Zoarium short, clavate E, nidulata. 



b. Apertures mostly in linear series. = Spiropora. 



a. Apertures in regular horizontal rows : 



(1) series of apertures distant S. elegans. 



(2) series of apertures close S. annulosa. 



b. Apertures in oblique spiral series : 



(1) peristomes slightly raised S. ccespitosa. 



(2) peristomes well raised 8. richmondiensis. 



c. Apertures in short alternate series S. tetragona. 



II. Branches stout, with a central dense axis. 



= Ceriocava. 



(1) Axis thick C. corymbosa. 



(2) Axis loose and irregular C. laxata. 



B. Zooecia short and hexagonal ; apertures contracted. 



= Haplooscia. 



(1) Apertures regularly arranged H. straminea. 



(2) Apertures irregularly arranged H. irregularis. 



Ann. (k Mag. N. Hist. JSer. 6. Vol. xvii. 14 



