292 Systematic Paleoxtology — Middle Devonian 



the importance of these earinate ridges in tracing the development of 

 these species. 



Length, greater than 15 mm. ; width. ]irobahly more than 16 mm. 



Occurrence. — Eomney Fop.mation. Hamilton JNIember. Williams 

 Road about 3i miles soiitlieast of Cnuihi-'rland and near the top of the 

 Hamilton. 



Collection. — Maryland Geological Snrvey. 



CyCLONEMA ( ?) MARYLANDENSE n. Sp. 



Plate XXXVI, Fig. 10 



Desa-iption. — Shell subconical ; vidth across the last volution a little 

 less than the height (in this specimen about |ths) ; volutions four. Body- 

 whorl rather ventricose, upper portion sloping gradually from the suture 

 to its conspicuous ventricose part; the entire surface marked by revolving 

 elevated lines of similar and medium strength of which there are about 

 eighteen on the Iwdy-whorl, and eight or nine on the second whorl. 



In the number of revolving lines this specimen agrees quite closely with 

 Cyclonema hamiltoniae Hall; but differs markedly from it in the grad- 

 ually sloping upper part of the body-whorl marked by revolving lines 

 while in the species just cited that part of the body-whorl is more or less 

 flattened and smooth. 



The collection contains but a single specimen of this species from west- 

 ern ]\Iaryland, the exact locality of M'hich is unknown, which was sub- 

 mitted to Dr. Grabau who wrote as follows: " I suppose the best thing to 

 do would be to refer this to Cyclonema. I am, however, inclined with 

 Ulrich to hold that there are no true Cyclonemas in the Devonic. The 

 present specimen appears to be a more primitive type than the Ordo\acic 

 Cyclonemas, since the spiral lines are simple, i. e.. only primary ones — as 

 near as can be determined from this specimen — while typical Cyclonema 

 eg. hilix Conrad has intercalated spirals. Hall's C. doris from the Scho- 

 harie is not unlike this, though I suspect his specimen was broken at the 

 base. I should advise describing this specimen as Cyclonema (?) n. sp." 

 Ulrich has expressed the following opinion regarding the Devonian Cy- 



