NO. 1192. TBENTON FAUNA OF BAFFIN LAND— SCBUCHEET. 157 



The Arctic examples are large and robust, and ajjjree rather with speci- 

 mens from Watertown, IsTew York, than with those from Minnesota, 

 which are somewhat smaller. The species is often confounded with 

 Orthis {HeberteUa) horealis, but can be easily distinguished by the 

 almost entire absence of fold and sinus. When these are present, how- 

 ever, they are found to occupy a position the reverse of that seen in the 

 latter species. 



Collectors. — J. N. Oarpender, A. V. Shaw, and A. H. White. Cat. 

 No. 28150, U.S.N.M. A number of specimens collected by Mr. K. W. 

 Porter are in the American Museum of Natural History. 



ORTHIS (HEBERTELLA) BOREALIS (Billings). 



Orthis (Hehertella) horealis Winchell and Schuchert, Geol. Minn., Ill, Pt. 1, 

 1893, p. 433, figs. 33a-33c. 



This well-developed species is represented by six typical specimens. 

 They much resemble 0. (P.) plicatella externally except in the position 

 ot the fold and sinus, which is the reverse of that seen in Hall's 

 species. 



Collector. — J. N. Carpender. In the American Museum of Natural 

 History there are three specimens collected by E. W. Porter. Oat. 

 No. 28151, U.S.N.M. 



ORTHIS (HEBERTELLA?) BELLIRUGOSA (Conrad). 



Orthis {Hehertella?) hellarugosa Winchell and Schuchert, Geol. Minn., Ill, 

 Pt. 1, 1893, p. 434, pi. XXXIII, figs. 1-4. 



This species is never abundant in the Trenton, and the same is true 

 in Baffin Land. Mr. Russell W. Porter found a single specimen, which 

 is now in the American Museum of Natural History. This form also 

 occurs on Akpatok Island, Ungava Bay, Labrador. 



ORTHIS (DINORTHIS) MEEDSI Winchell and Schuchert, var. ARCTICA, 



. new variety. 



(Plate XII, figs. 7, 8.) 



Orthis (Dinorthis) meedsi Winchell and Schuchert, Geol. Minn., Ill, Pt. 1, 

 1893, p. 427, pi. XXII, figs. 39-45. 



This species, which is common in the Galena or Trenton stage of 

 Minnesota, is also abundant at the Frobisher Bay locality. As in Min- 

 nesota, it is here also a very variable species. However, among the 

 Arctic specimens this variation tends toward the equalization and 

 increase of the number of plications, while in Minnesota, bundling of 

 the plications accompanied by the development of a conspicuous dorsal 

 sinus, is the chief trend of variation. The specimens having the last- 

 named characters were given the varietal name germana. On the same 

 ground it may be advisable to name the Arctic variation — those with 

 the more numerous and equal plications, and an obsolete or nearly obso- 

 lete dorsal- sinus variety — arctica. 



