EARLY PALEOZOIC BRYOZOA OP THE BALTIC PROVINCES. Ill 



Occurrence. — Rare in the Glauconite limestone (B2) at Pawlo"vsk, 

 government of St. Petersburg. 



Holotype.—Csit. No. 57208, U.S.N.M. 



A thin section of the type-specimen is in the collection of the British 

 Museum. 



Genus CHILOTRYPA Ulrich. 



Cheilotrypa Ulrich, Joum. Cincinnati Soc. Nat. Hist., vol. 7, 1884, p. 49. 



Chilotrypa Miller, North Amer. Geol. and Pal., 1889, p. 297. — Ulrich, Geo!. 

 Surv. Illinois, vol. 8, 1890, p. 382; Zittel's Textbook of Paleontology (Eng. ed.), 

 1896, p. 269. — Simpson, Fourteenth Ann. Rep. State Geol. New York for the 

 year 1894, 1897, p. 554.— Nickles and Bassler, Bull. 173, U. S. Geol. Surv., 

 1900, p. 26.— Bassler, Bull. 292, U. S. Geol. Surv., 1906, p. 24. 



The zooecial characters of this genus are essentially the same as in 

 Fistulipora, but the zoarium is of small, ramose branches with a 

 narrow, irregularly expanding and contracting axial tube. The 

 genus may be said, therefore, to be the equivalent in the Fistuli- 

 poridse of {Jcdoclema in the Ceramoporidae. The following species 

 is the earliest known, and naturally has primitive characters. 



Genotype. — Chilotrypa Mspida Ulrich. Mississippian of the United 

 States. 



CHILOTRYPA IMMATURA, new species. 

 Text fig. 41. 



Zoarium of very narrow, irregularly cylindrical, smooth branches, 

 about 1 mm. in diameter, with small, macular areas at intervals of 

 2.5 mm. Apertures with their proximal end slightly raised into a 



Fig. 41.— Cheloteypa immatura. a, a fragment, X2, with a few zocecial apertures enlarged; 6, 



TANGENTIAL SECTION, X20, SHOWING AEEANGEMENT AND SHAPE OF ZOCECLA; C, VERTICAL SECTION, X20, 

 WITH EXPANDING AND [CONTRACTING CENTRAL TUBE; d, TRANSVERSE SECTION, X20, SHOWING CENTRAL 

 TUBE AND THICKNESS OF ZOARLAL LAYER. LYCKHOLM LIMESTONE (Fl), KERTEL, ISLAND OF DAQO, 

 ESTHONIA. 



lunarium, arranged in ascending spiral rows, elongate oval, five in 

 2 mm. Interzooecial spaces closed at the surface. Ends of branch 

 show the hollow, axial tube, about 0.16 mm. in diameter. The tube 

 is a prominent feature of vertical sections, where it is seen to slightly 

 expand and contract. Such sections also show the zocecia to arise from 



