62 Professor J. W. Gregory — New Cretaceous Bryozoa. 



above is roughly triangular. The head includes about ten bundles of zooecia , which 

 rise upward in sharp spikes. The bundles are grooved longitudinally and branch 

 dichotomously ; the sides, when worn, appear punctate, but in well-preserved 

 specimens are marked with longitudinal ridges, decorated by small points. 



Bistrihiition. — England — Chalk : South-east of England. Eoreign — 

 Senonian (Campanian) : Ciply. 



E,etenoa/ nov. gen. 



Diagnosis. — Theonoidte with an erect frondose zoarium, composed of a network of 

 dichotomous, anastomosing branches. The apertures all open on one face of the 

 zoarium. 



Type Species. — Retenoa campicheana (Orb.), 1853. Neocomian: 

 Sainte-Croix, Switzerland. 



HomceosolejST, Lonsdale, 1850. 



Somceosolen gamllei, n.sp. 



Diagnosis. — Zoarium frondescent, of crowded multipinnate branches. The 

 branching is irregular ; the branchlets cross and intersect, but do not anastomose. 

 The back of the distal parts of the branches is traversed by longitudinal, fluted, or 

 carinate ridges, which form a strong median carina; but this structure may be 

 replaced by transverse wrinkling in the proximal ends of the branches in old 

 specimens. Gonoecia ovoid ; attached to base of the pinnules on the obverse face. 



Distribution. — Upper Chalk (zone of Micraster coranguimim) : 

 Gravesend ; Bromley, Kent. Middle Chalk (zone of Micraster 

 cortestudinariuni) : Chatham. Also from Chalk, zones not recorded, at 

 €haring, Kent ; Salisbury ; Guildford ; Arreton Down, Isle of Wight. 



Somceosolen virgidosa, n.sp. 

 Diagnosis. — Zoarium an erect, irregular tuft, which is repeatedly branched. The 

 branching is irregularly dichotomous. The peristomal bundles are transversely 

 elongated, and may occur in biserial ridges with as many as five apertur-es in each 

 horizontal, transverse row. Some grou]3s of apertures are ii'regularly triserial. 

 Reverse surface fluted. 



Distribution. — Chalk (zone of Micraster cortestudinariuni) : Chatham. 

 DiscocYTis, d'Orbigny, 1854. 

 Discocytis profunda, n.sp. 

 Diagnosis. — Zoarium very small, solid, pointed below, and expanding gradually 

 or rapidly upward to an irregular but horizontal upper sui-face. The sides are 

 coarsely ridged. Apertures in groups on irregular blunt knobs around the margin of 

 the upper surface ; seen from above the groups are radial and separated by irregular, 

 small zocecia. 



Distribution. — Chalk: Charing, Kent. 



Desmepora, Lonsdale, 1850. 



Desmepora hlaclcmorei, n.sp. 



Diagnosis. — Zoarium of flat, broad branches. The apertures open on the ends of 

 short, ridge-like lateral processes which project along the sides of the stems ; these 

 lateral processes are irregularly elliptical ; the apertm-es are generally biserial with 

 about eight in each row of a process, and the series are placed horizontally. The 

 reverse sm-face is covered by crowded rows of small round pores (cancelli),"and the 

 surface is slightly concave. 



Distribution. — Upper Chalk (zone of Actinocamax quadratus) : East 

 Harnham, near Salisbury. 



1 An abbreviation of Rcte-theonoa, the theonid with a net-shaped zoarium. 



