520 PALEONTOLOGY OF ILLINOIS. 



Fragments of this species might be confounded with a St. 

 Louis limestone species of Dichotrypa, but the nearly complete 

 example before me clearly proves the species to be a Glypto- 

 pora. 



Position and locality: Chester group. Rare at some locality 

 in Monroe Co., 111. 



EURYDICTYA Ulrich. 



(For generic diagnosis see page 389.) 



This genus includes a small group of Silurian Bryozoa that, 

 though intimately related to Stictopora Hall (Rhinidictya 

 Ulrich), it seems desirable to distinguish from that genus. The 

 broad and undefined zoarial expansion pertaining to the sev- 

 eral species gives to them a very different aspect from that 

 presented by the parallel margined, dichotomously divided, 

 narrow stipes, so strictly adhered to by the true species of 

 Stictopora. The two genera stand precisely in the same relation 

 to each other as Cystodictya and Dichotrypa. 



In addition to the three species here defined the genus will 

 include Phsenopora multipora Hall, of which a full description 

 is given in my "American Palaeozoic Bryozoa," (Jour. Cin. Soc. 

 Nat. Hist., vol. V, p. 171). At that time I stated the species 

 was most probably not congeneric with typical Phsenopora 

 Hall. That supposition has since been verified. 



EURYDICTYA CALHOUNENSIS Ulrich. 



PI. XXX, Fig. 4-4c. 



Zoarium an expanded frond; thickness two mm. Surface 

 smooth with maculae which are irregular in size, elevation, and 

 distribution. Zooecia arranged in longitudinal series; the super- 

 ficial apertures have the appearance of being between raised 

 longitudinal lines; generally oval, occasionally sub-circular, be- 

 tween six and seven in two mm. measuring lengthwise. Inter- 

 spaces between the ends of two successive apertures about equal 

 to or less than the long diameter of the apertures. Minute 

 tubuli, appearing on the surface as granules, are arranged in a 

 flexuous line between adjacent series of cells and in one or two 

 irregular rows in the end interspaces. Macute consist of a large 



