NO. 1442. JAMES TYPES OF BRYOZOA—BASSLER. 19 



is the same as BatoHtoma varians (James), while the second is a good 

 species of the same genus. The writer proposes to restrict the spe- 

 cies Batostoma varlalyUe to the second form. Ilhistrations of the 

 external features of this form have alread}" been published by Ulrich, 

 as cited above, and figures of the internal structure are given on Plate 

 VII of this article. 



B. vai iahilt\ as thus restricted, forms robust, cylindrical or subcom- 

 pressed usually infrequently dividing stems, 10 mm. or more in diam- 

 eter. The surface of the zoarium is smooth but macuhv of conspicu- 

 ously larger zooecia are present. The zooecia are thin-walled and 

 angular at the surface with mesopores practically absent. Below the 

 surface the zooecial walls are so thickened by deposits of tissue along 

 their sides that a tangential section through this region gives a 

 rounded aspect to the apertures. Six to seven of the ordinary zooecia 

 occur in 2 mm. Acanthopores sometimes large and occupying all the 

 zooecial angles, but at other times not a conspicuous feature. Distribu- 

 tion of diaphragms and other internal features as shown on Plate VII. 



Because of the absence of mesopores, this species shows with unu- 

 sual distinctness in tangential sections, the black line separating the 

 walls of contiguous zooecia, a characteristic feature of this as well as a 

 number of other genera of the monticuliporoids. The lai-ge, smooth, 

 ramose zoarium, angular contiguous zooecia, few mesopores, and con- 

 spicuous clusters are characters sufficient to distinguish this form from 

 other species of the genus. 



The specimens figured b}' Ulrich from the Richmond group at 

 Savannah, Illinois (Plate XXXV, figs. 4, -la, in the work cited above) 

 can not be determined with certaint}' on account of their ill-preserved 

 internal structure, but it is probable that thej" belong to neither of 

 the two species under discussion. 



Oecurrenee. — Uppermost beds of Richmond group at a number of 

 localities in Indiana and Ohio. The types which are in the collections 

 of the U. S. National Museum, were found in the vicinit}' of Osgood, 

 Indiana. 



BYTHOPORA ARCTIPORA (Nicholson). 

 Plate II, tigs. 1, 2. 



Ptilodictya f arcUpora Nicholson, Ann. ]Mag. Nat. Hist. (4), XV, 1875, p. 180, 



pi. XIV, figs. i—ih. 

 Ptilodictya f arctipora Nicholson, Geol. Snrv. Ohio, Pal., II, 1875, j). 262, pi. xxv, 



figs. 9-9h. 

 Bytliojiora urctipora Miller and Dyek, Contr. to Pal., No. 2, 1878, p. 8. 

 ChMeies minutus James, Paleontologist, No. 3, 1879, p. 20. 



The tj'pes of Chaetetes ininidus. James consist of a number of speci- 

 mens of a small species of Bythojxn'a. Carefully compared with other 

 species of this genus, the}^ all prove to be more or less youthful 

 branches of the same species of which Nicholson had previously 



