124 THE PALEONTOLOGY OP MINNESOTA. 



[Rhinicllrtya. 



Suborder CRYPTOSTOMATA, Vine. 



Family RHINIDIOTYONID^, n. fam. 



Stictoporidae, ULRICH, 1890. Geol. Surv. 111., vol. viii, p. 388. 



Stictoporidce (part.), ULUICH, 1882. Jour. Cin. Soc. Nat. Hist., vol. v, p. 152. 



This name is proposed instead of Stictoporidce, for the reason that the type genus 

 is not, as I have heretofore held, properly expressed by the term Stictopora. Since 

 Hall, the author of that name, and others, insist that 6'. elegantula is the type of Stic- 

 topora, it follows that the genus and family as described by me (loc. cit.) cannot stand. 

 In my Illinois work, namely, I had taken the stand that S. fenestrata is to be regarded 

 as the type, and as that species is unquestionably congeneric with Ehinidictya, Ulrich, 

 (Jour. Cin. Soc. Nat. Hist., vol. v, p. 152), the latter was reduced to synonomy. Though 

 the minute internal and external details of structure of S. elegantula have not yet 

 been made public, enough is known of it to prove conclusively that it represents a 

 genus to which S. fenestrata has no claim. This being the case, Ehinidictya will 

 stand and include fenestrata* 



Genus EHINIDICTYA, Ulrich. 



Stictopora (part.), HALL, 1847. Pal. N. Y., vol. i, p. 73. 

 Stictopora, ULBICH, 1890. Geol. Surv. 111., vol. viil, p. 388. 



Rhinidictya, ULRICH, 18S2. Jour. Cin. Soc. Nat. Hist., vol. v, p. 152; HALL, 1887, Pal. N. Y., 



vol. vi, p. 20. 



" Zoaria composed of narrow, compressed, dichotomously divided branches, with 

 the margins sharp, straight, and essentially parallel ; attached to foreign bodies 

 by a continuous expanded base. Zooecial apertures subcircular or elliptical, arranged 

 alternately in longitudinal series between slightly elevated, straight or flexuous ridges, 

 carrying a crowded row of small blunt spines. Space immediately surrounding aper- 

 tures sloping up to summits of ridges." (Geol. Surv. 111., vol. viii, p. 388.) 



Type: E. nicholsoni Ulrich, Birdseye Limestone, Kentucky. 



This genus finds its strongest development numerically, both as regards species 

 and individuals, in the rocks of the Trenton formation. The Minnesota shales of 

 this group are especially rich in specimens, and so far as species are concerned, there 

 is no other section of the country from which as many are known. Unfortunately, 

 however, the various forms of the genus are not by any means easily distinguished 

 from each other. It is true also that of those species which have a wide geographi- 

 cal range, as for instance from Minnesota to Kentucky and Tennessee, or to New 



* For objeotions to the use of SuUopora, d'Orb., Instead of RMnidictya, see Geol. Surv. 111., vol. viii, pp. 683 and 687. 



