JAME.S TYPES OF BE VOZOA—BASSLEli. 41 



quently dividing .stems coiimionly varying between 4 and 8 mm. in 

 diameter. Tlie middle Eden form, however, is more robust, the 

 branches being- subcyiindrical or compressed and usually over 10 mm. 

 in width. In all other respects the two forms are alike. 



Surface smooth, with maculae composed of zocecia larger and meso- 

 pores more numerous than in the intervening spaces. Zocecia large, 

 rather thin-walled, polygonal, 5 of the normal size in 2 mm. Meso- 

 poies angular, few among the ordinary zocecia, more numerous in 

 the macuhe. Acanthopores seemingl}^ absent and, if developed at all, 

 small and inconspicuous. 



In internal structure the most marked feature is the presence of semi- 

 diaphragms in the peripheral region of the zocjecial tubes. Besides 

 these, vertical sections as well as vertical fractures show the zooecial 

 walls in the axial region to be strongly crinkled. The zooecial tubes 

 ill this region are almost entirely without diaphragms. The mesopores 

 which develop in the peripheral region only, are crossed by the usual 

 straight complete tabulae. Tangential sections show thin-walled polyg- 

 onal zooecia, few mesopores and apparent absence of acanthopores, but 

 bring out especially the dark line separating adjoining zooecia. 



H. fvMtfeldi is closely related to and is probably a descendant of 

 the Trenton species Ilentipliragwa tenidmurale Ulrich," but the more 

 robust growth and several internal features, particularly the crinkled 

 walls, of the species under consideration will suffice in distinguishing 

 the two. Of associated bryozoa none approaches H. \nhitfieldi closely 

 enough to require comparison. 



< heuTTence. — Abundant and characteristic of the lower (Economy) 

 and middle (Southgate) divisions of the Eden shale at Cincinnati, Ohio, 

 and vicinity. 



HOMOTRYPA WORTHENI (James). 



Moniiculvpora [Monotryp(i) irorUieui James, Paleontologist, No. 6, 1882, p. 50; 



No. 7, 1883, pi. I, 'fig. 2. 

 Monticulipora wortheni James and James, Jour. Cincinnati Soc. Nat. Hist., X, 



1888, p. 184, pi. II, figs. 3a, b. — J. F. James, Jour. Cincinnati Soc. Nat. Hist., 



XVI, 1894, p. 207. 

 Hornotrypa vortheni Basslek, Proc. U. S. Nat. Mus., XXVT, 1903, j). 583, 



pi. XXIV, figs. 10-14. 



Both the internal and external features of this species were described 

 and illustrated by the writer in 1903,* this conception of the species 

 being based upon specimens in the collection of the U. S. National 

 Museum with Mr. James's labels attached. A comparison of these 

 specimens with the types shows that all are of the same species. 



II. wortheni is a characteristic fossil of the Whitewater member of 



" Ulrich, Geol. Nat. Hist. Surv. Minn., Final Rep., Ill, Pt. 1, 1893, |). 301, ])l. xxiv, 

 tigs. 20-23. 



n^roc. U. S. Nat. Mus., XXVI, 1903, p. 583. 



