THE 



GEOLOGICAL MAGAZINE 



NEW SERIES. DECADE VL VOL. L 



No. IIL— MARCH, 1914. 



OI^IG-Ilsr^^Il. .A-IiTIOLEJS. 



I. — Notes on' new or imperfectly known Chalk Polyzoa. 



By E. M. Brydone, F.G.S. 



{Continued from Dec. Y, Vol. X, p. 438.) 



(PLATE IV.) 



Cribrilina cicatricifera, sp. nov. (PI. IV, Figs. 1, 2.) 



Zoarium unilaminate, adherent. 



Zooecia convex, quite separate, very small, average length '35 to 

 •38 mm. and width -2 mm. ; numerous radiating imperforate lines 

 are faintly perceptible on some of them in a suitable light, and 

 were doubtless present on all; they are hardly 'furrows', resembling 

 rather superficial cuts ; apertures very slightly heel-shaped. 



Ocecia abundant, relatively large, globose with a strongly concave 

 free edge. 



Avictilaria perhaps represented by the tiny bodies like abortive 

 zooecia, with long, narrow apertures which are scattered freely over 

 the zoarium. 



This dwarf form occurs sparingly in the zone of M. cor-anffuitium, 

 and probablj^ persists in small zoaria up to the Wey bourne Chalk. 



Cribrilina vulnerata, sp. nov. (PI. IV, Figs. 3, 4.) 



Zoarium unilaminate, adherent. 



Zooecia convex, quite separate, small, average length '4 to '42 mm. 

 and width '3 mm., with a few radiating imperforate lines, I'esembling 

 (but rather more marked than) those of C. cicatricifera, visible on 

 many ; apertures marlcedly horseshoe-shaped, rather variable in size ; 

 low down at the upper end a well-marked pore often occurs. 



Ocecia very large and globose, with a deeply concave free edge, 

 enveloping the upper part of the aperture; they are very abundant, 

 but very fragile, the specimen sliown in Fig. 3 being almost the only 

 one I have seen ; the broken edges present an appearance quite 

 distinctive under a pocket magnifier. 



Avicularia >inknown. 



This species is abundant in the Triraingham Chalk and occurs 

 sparingly in the Wevbourne Chalk. Comparison with the type of 

 Cellepora megastoma, Desm. & Lesueur,^ might show a relation with 

 that species, the figure of which is quite inadequate. 



This and the foregoing species clearly illustrate the last stage before 

 the final consolidation of a Cribrilinid front wall. 



1 Bull. Sci. Philomathiques, 1814, p. 54, pi. ii, fig- 5. 

 DECADE VI. — VOL. I. — NO. III. 7 



■14 1914 



) 



