26 BULLETIN 6"), UNITED STATES NATIONAL MUSEUM. 



hi other phices, modos of connection ( coaIcsc-cnc(> of approxinuited lateral mar- 

 ;;ins. cnrviiifr together and entire fusion of adjacent branches) usual in Des- 

 mograittufi, thus producing a great variety of mesh form, constitutes a striking 

 feature in the present species. 



This species is one of the most common groptolites in the Rochester 

 shale of New York, as well as in the limestone at Hamilton, Ontario. 

 Quoting Doctor Kuedemann : 



This form is easily distinguished from both its associated congeners, D. rrti- 

 fnrmc and D. grncUc, by its more irregularly l)ent branches and the oblique 

 direction of the dissepiments. By these characters it seems to lead directly to 

 Calyptograptiis subrctifonnis Spencer with which it is also associated. 



Fig. 29. — Dictto.vema POLXMORriiiM Gurley. SrENCER's figured type of Dicttoxema 



TEXELLUM. (AFTER SPENCER.) 



Holotype (selected by Kuedemann). — Cat. No. 54278, U.S.N.M. 

 Plemotype. — AValker Museum, University of Chicago, No. 13517. 



DICTYONEMA SUBRETIFORME (Spencer). 



Calyptograpaiix siihrrtiforniis Spenckr, Canadian Nat., VIII, 1S7S, pp. -io^. 



460. 

 Calyptograptus subrctifnruiis Spencer, Trans. Acad. Sci. St. Louis, IV, 1SS4, 



p. 578, pi. 4, fig. 1 (not fig. 2) ; Bull. Mus. Univ. State Missouri, I, 1884, 



p. 28, pi. 4, fig. 1 (not fig. 2). 

 Dictyonema subrctiformc Kuedemann, New York State Mus., Mem. 11, 1908, 



p. 162, pi. 2, figs. 1, 2. 



This species is closel}' related and similar to the preceding form, P. 

 pohj/norphum, both of which have been described and illustrated by 



