JAMES TYPES OE BRYOZOA—BASSLER. 51 



parallel longitudinal series. The internal structure is essentially the 

 same as that figured by Ulrich for P. magnified Miller and Dyer." 



The types of PtHodictya cUntcmensis are straight, parallel-edged, 

 smooth, unbranched fronds less than 3 mm. in width, and agree in all 

 respects with numerous other examples regarded as young zoaria of 

 P. nodoxa. 



Ptilod/ctya tere-s was distinguished by its author mainly because the 

 zoarium in the specimen described bears '"six or seven rows of oval 

 pores, on the upper part, arranged in an alternating manner between 

 exceedingly delicate raised lines." The general shape and a thin sec- 

 tion of the type indicate that P. tere.s also is a synonym of P. nodoxa, 

 being merely an unusual or perhaps al)ortive example of that species. 

 The oval pores mentioned by James are of zocjecia, the zocecial aper- 

 tures being of this shape and arranged between raised lines on the 

 striated basal parts of all ptilodictyoid bryozoa. 



Occurrence. — Whitewater formation of the Richmond group. The 

 types of P. nodosa., and also of its two synonyms, came from Clinton 

 County, Ohio, where the species seems more abundant than elsewhere. 



PTILODICTYA PLUMARIA James. 



Pfilodictya phimaria James, Paleontologist, No. 1, 1878, p. 4. 

 Ftilodictya plumaria TTlrich, Jour. Cincinnati Soc. Nat. Hist., V, 1882, j)!. vii, 

 figs. 1, la. 



This species resembles the preceding P. nodom in its general zooecial 

 and surface characters, but differs in this that, instead of being sword- 

 shaped, the zoarium expands rapidly from the pointed striated base 

 into a leaf-like frond sometimes exceeding 25 mm. in diameter. A 

 typical specimen of the species was figured by Ulrich.'' 



The three Richmond species of Ptilodictiia^ P. nodosa., P. plutitarla^ 

 and P. indgriifica Miller and Dyer, form a series, the first comprising 

 long, rather narrow, parallel-edged fronds, the third forming broad 

 and rather irregular expansions, while the second is intermediate in 

 its zoarial shape. A similar relationship is exhibited by the three 

 Fairview species of Esclmropora^ E. falclforniU., E. inaeidata^ and 

 E. pavonia. In both of these groups of bryozoa the shape of the zoarium 

 is within reasonaV)le limits, fairly constant, and afl^ords a ready means 

 of distinguishing the species. 



Occu/rrence. — James's t3'pe is from Warren Connt3\ Ohio, but the 

 species occurs at a number of localities in southwestern Ohio and 

 southeastern Indiana, where the Whitewater formation of the Rich- 

 mond, to which beds these three forms of Pfilodictya are restricted, 

 are exposed. 



^'Geol. Surv*^ Illinois, VIII, 1890, p. 391, figs, lla-c. 



''Jour. Cincinnati .Soc. Nat. Hist., V, 1882, pi. vii, figs. 1, la. 



