SPECHTS FERRY BRYOZOAN FAUNA 25 



displays a poorly developed mature zone, and has somewhat more abundant dia- 

 phragms in the axial region than the holotype. Zooecial apertures in the tangen- 

 tial section of the paratype are somewhat elongate as the zooecia are inclined 

 slightly to the zoarial surface. 



The three tangential sections commonly show angular or subround cells 

 that are smaller than normal zooecia and consequently simulate mesopores. Longi- 

 tudinal and transverse sections, however, do not reveal small closely tabulate or 

 moniliform tubes, and thus the writer concludes that mesopores are absent. Ulrich 

 and Bassler (1904, p. 44) suggest that Monotrypella is a rare and probably unique 

 genus, although Bassler (1953, p. G109) still recognizes its validity at a much 

 later date. Structural characteristics of the specimens under study, however, 

 dictate their assignment to Monotrypella . The specific name has been selected to 

 indicate that this species has all the structural characteristics of its genus. 



The closest relative to Monotrypella normalis is the type species of the 

 genus, M, aequalis Ulrich, from the Eden (early Cincinnatian), which differs from 

 M. normalis in having larger zooecia and in virtually lacking diaphragms in the 

 axis. 



Distribution. — Localities 6, 10. 



Types. — Illinois State Geological Survey; holotype 12P68, paratype 12 P216. 



Family TREMATOPORIDAE Miller, 1889 



Genus BATOSTOMA Ulrich, 1882 



Type species: Batostoma implication (Nicholson) 



BATOSTOMA WINCHELLI SPINULOSUM Ulrich 



Plate 5, figures 4-6 



Batostoma winchelli var. spinulosum Ulrich, 1895, Geol . Minnesota, 

 v. 3, pt. 1, p. 296, pi. 27, figs. 7, 8; Zittel, 1896, 

 Textbook of Paleont . (Eng . edit.), p. 275, fig. 459C; 

 Bassler, 1911, U. S. Nat. Mus. Bull. 77, p. 279, figs. 167, 168; 

 Fritz, 1957, Geol. Survey Canada Bull . 42, p. 12, pi. Ill, 

 figs. 1, 2. 

 External features. — Zoarium ramose, the incomplete specimen 29 mm long 

 and 7 mm in diameter. Acanthopores clearly visible, mainly at junction angles of 

 adjoining zooecia, as dark, slightly protuberant spines. Maculae not common, 

 irregularly distributed, flush with surface, and composed of about four to seven 

 zooecia above average in size and two or three associated mesopores. 



Tangential section. — Zooecia subangular and generally having broadly 

 ovate or somewhat irregularly shaped apertures that are commonly inflected by 

 prominent acanthopores; most commonly (seven of ten measurements) six entire 

 zooecia and part of seventh in 2 mm, measuring parallel to length of zoarium; less 

 commonly (two of ten measurements) five complete zooecia and portion of sixth or 

 (one of ten measurements) seven entire zooecia and part of eighth in this distance; 

 average maximum apertural diameter of zooecia, exclusive of zooecial walls, 0.26 

 mm, ranging from 0.23 to 0.28 mm for ten measurements. Acanthopores abundant, 

 generally four to six associated with each zooecium, occupying most junction 

 angles of adjoining zooecia and also in zooecial walls between junction angles, 

 usually ranging in diameter from 0.04 to 0.07 mm, and commonly inflecting zooecial 

 apertures strongly. Mesopores moderately common. Cluster of about four zooecia 

 above average in size and associated mesopores represent a macula. 



