SPECHTS FERRY BRYOZOAN FAUNA 31 



Genus DIPLOTRYPA Nicholson, 1879 



Type species: Diplotrypa petropolitanus (Pander) 



DIPLOTRYPA sp. 



Plate 5, figures 7, 8 



External features. — Zoarium a nearly circular sheetlike growth, 9.5 mm in 

 diameter and slightly less than 2.0 mm thick, attached to a brachiopod valve. Clus- 

 ter of four zooecia slightly above average in size may represent macula. 



Tangential section. — Zooecia nearly circular or broadly ovate and having 

 walls of moderate thickness (about 0.02 mm or slightly less) composed of fine 

 laminae parallel to apertural periphery; most commonly (seven of 12 measurements) 

 six entire zooecia and part of seventh in 2 mm; less commonly (five of 12 measure- 

 ments) five entire zooecia and portion of sixth in this distance; average maximum 

 apertural diameter of zooecia, not including zooecial walls, 0.30 mm, ranging 

 from 0.27 to 0.35 mm for 16 measurements. Adjacent zooecia locally in contact 

 but partially separated by mesopores. Cluster of four zooecia somewhat above 

 average in size represents macula. Acanthopores not observed. 



Longitudinal section. — Zooecia erect, of nearly uniform wall thickness 

 throughout length, and usually containing five or fewer diaphragms per zoecium; 

 diaphragms mainly localized in lower half of zoarium. Mesopores abundant, 

 closely tabulate. 



Remarks. — This genus is represented in the collections by a single rather 

 poorly preserved specimen from which one longitudinal and two tangential sections 

 were obtained. Because of the small size of the sections and unfavorable preser- 

 vation, the specimen could not be compared adequately with previously described 

 species of the genus. 



Distribution. — Locality 10. 



Described specimen. — Illinois State Geological Survey, 12P207. 



Order CRYPTOSTOMATA Vine, 1883 



Family STICTOPORELLIDAE Nickles & Bassler, 1900 



Genus STICTOPORELLA Ulrich, 1882 



Type species: Stictoporella interstincta Ulrich 



STICTOPORELLA FRONDIFERA Ulrich 



Plate 7, figures 1-9 



Stictoporella frondifera Ulrich, 1886, 14th Ann. Rept . , Geol. Nat. 

 Hist. Survey Minnesota, p. 72; Ulrich, 1895, Geol. Minnesota, 

 v. 3, p. 183, pi. XI, figs. 12-19. 



External features. — Zoarium a bifoliate leaflike or palmate expansion, the 

 largest incomplete specimen 45 mm long and 37 mm wide, generally less than 2 mm 

 thick, and commonly showing flat lobes or compressed incipient branches extend- 

 ing from the main zoarial mass. Zooecial apertures broadly ovate to polygonal and 

 surrounded by thick walls. Maculae sporadically distributed but commonly 3 to 

 4.5 mm apart, measuring from center to center, and usually composed of approxi- 

 mately eight to twenty mesopores; elsewhere, mesopores rare to common. 



Tangential section. — Zooecia angular, thick-walled, and having broadly 

 ovate to subcircular apertures; most commonly (212 of 382 measurements on 39 



