42 BULLETIN OF THE LABORATORIES 



pean authors, with S. cuspidatus. ^rhe wide range of variation and 

 distribution make this an exceedingly valuable species for approxi- 

 mately synchronizing widely distant horizons, for its vertical range is 

 not extraordinary. The subjoined table of measurements and data 

 will serve our present purpose in connection with the figures. In the 

 view here indicated Prof. Winchell does not concur, as may be gath- 

 ered from the extract from a private letter of Jan. 9th, 1888, from 

 which I take the liberty to quote. 



" I have heretofore identified with this species some specimens 

 from Newark, Ohio, embracing both ventral and dorsal valves. I re- 

 ceived some time since, from Prof. Hicks, specimens from Granville, 

 labeled 6" Carteri^ among which is a ventral valve resembling forms 

 identified by me with Syringofhyris typi/s ; but his dorsal valves differ 

 from those of S. typiis in having the hinge extremities prolonged and 

 pointed; in more rigid costic and lack of situation in the middle of the 

 anterior margin. They also lack the deep concentric wrinkles of the 

 dorsal valve of .S". typus. I hence separate these dorsal valves from 

 Granville from S. typus, and leave them to represent 6". Carteri'"' 



Fig. 17, of Plate II, serves to illustrate the usual form of the 

 smaller and more finely striate form called S. carteri, though these 

 often have acuminate angles The difference between such forms and 

 those figured 4-6 Plate V. is coixipletely bridged, nor does it seem 

 possible to exclude the extreme variety drawn in Fig. 7, Plate I. 



The species reaches its maxinium in the congl. II, but is charac- 

 teristic of our middle division, beyond which it extends somewhat 

 both above and below. 



Spirifers of the S. inarionensis ^roup. 



This is the most perplexing subdivision of the genus. Four nom- 

 inal species contend for admission and present characters so concor- 

 dant as almost to baffle discrimination. These species are S. striati- 

 formis. Meek, 5. cent7'onata. Win., .S". biplicatus, Hall, and S. inarion- 

 ensis, Shumard. All of these have been at some time identified in 

 Ohio. S. striatiformis alone presents such peculiarities as make it 

 easily identified when perfectly preserved. The S. biplicatus described 

 by Meek in the Ohio Palaeontology is stated by Winchell to be his S. 

 centronata, thus eliminating a second from the set. The following 



