52 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxx. 



PTILODICTYA WELSHI James. 



Pfilodich/a sp. (?) James, Paleontologist, No. 1, 1878, p. 8 (name Ptilodictya tvelshi 

 suggested ) . 



Under the caption of Pt'dodlctya sp. ? James described a Clinton 

 bifoliate bivozoan and suggested if it prove to be a distinct species 

 that the name Ptilodlvtya welxJii be applied to it. The type is either 

 lost or never formed a part of the James collection, but, judging from 

 the description, P. (oelshi is almost certainl}^ the same species as that 

 named and figured hy Van Cleve as E-schdva niultlfida in 1853 on the 

 plates of fossils which he distributed about that time. Van Cleve's 

 figure excellentl}^ represents his species, which was later described b}"^ 

 Hall" and is now referred to the genus PJi^nopora. If James's species 

 should prove to be the same, it ought to be considered a synonym for 

 Van Cleve's name since both appear in equally obscure publications and 

 the earlier figure of the one is of more service in recognizing the 

 form than the description of the other. 



Occurrence. — Clinton formation, Clinton County, Ohio. 



RHINIDICTYA PARALLELA (James). 



Plate II, figs. 5-7; plate V, figs. 2, .3. 



Ptilodictya parallela J AMES, Paleontologist, No. 1, 1878, p. 5. 



Rhiiiidictyd 2)cirallela Ulrich, Jour. Cincinnati Soc. Nat. Hist., V, 1882, p. 170. 



Ptl/odict!/(( granulosd James, Paleontologist, No. 1, 1878, p. 4. 



Original description of PtUodlctna j)araUela: ''Polyzoary, a tiat- 

 teued, linear, unbranched, two-edged frond, about one line wide, 

 longest example observed about one inch. Surface gently convex, 

 ceHuliferous on both faces; edges very thin and sharp. Eight or ten 

 alternating rows of elliptical cells arranged between longitudinal lines; 

 one row on each edge having an oblique direction. Cell apertures not 

 raised, five or six in the space of a line measuring longitudinally.'"' 



Numerous intermediate specimens in the IT. S. National Museum 

 prove beyond any question that the types of Ptilodictya paraUela and 

 P. grannhmt are founded upon ditferent stages of growth of one and 

 the same species, the type of the latter representing merely the more 

 mature or aged stage in which numerous granules develop. The defi- 

 nition of P. (/raiiNlosa precedes that of 1\ jxiiudlda in the Paleontolo- 

 gist, but the parallel -edged branches are so marked a character in this 

 species that the specific name calling attention to this fact is retained. 

 All species of RJi'ni'idictyn have a (jninitldsd stage, so that this name is 

 without any special significance. 



The straight, parallel -edged, seldom branching, bifoliate zoarium, 

 with the zocecia arranged in longitudinal rows, is so difi'erent from 

 associated bryozoa that no dilHculty is experienced in recognizing the 



"Twelfth Ann. Kcp. Indiana Geol. Nat. Hist, 1883, p. 268, pi. xiv, fig, 4. 



