284 NEW YORK STATE MUSEUM 



surcularis. The inference to be drawn from these occurrences is that 

 the differences of mode of growth between the two were smaller than the 

 flattened specimens would suggest, both having grown in upwardly directed 

 double spirals [sec 1 under N . gracilis, p. 280]. In surcularis, how- 

 ever, the main stipes formed a smaller axillary angle, were less curved and 

 more directly ascending, while in N . gracilis the)- were separated wider 

 at the base, had a greater curvature and diverged further from the axillary 

 plane of the rhabdosome. As a result of this the two stems in N . 

 gracilis were always, in becoming compressed, thrown to opposite sides 

 and the sigmoid curve produced, while in the variety surcularis they 

 were both turned to one side and became crossed, producing a r-like 

 figure. 



The sicula [fig. 197] has in this variety the same dimensions as in 

 the type species and is equally conspicuous ; besides it bears a long thin 

 sicular spine (virgella ?) and shows frequently a distinct nema. The two 

 primary thecae are horizontal and provided with small mucros, but the next 

 thecae grow already upwards. The main stipes attain but a small length 

 (about 10-17 mm) and small width (.3 mm). The secondary branches are 

 almost straight, seem not to number more than eight on either main stipe, 

 are about 7.5 mm long and but .4 mm to .5 mm wide; the component 

 thecae are closely arranged and number 10 to 12 in the space of 10 mm. 



The figures here given indicate that s u r c 11 1 a r i s is closer related to 

 the variety of N. gracilis here distinguished as N. gracilis var. 

 approximatus, than to the typical N. gracilis. The two varieties 

 have above all the close arrangement of the thecae and of the secondary 

 branches in common and as a corollary they also differ from the typical 

 gracilis by a greater rigidity of the branches, thereby assuming a 

 somewhat different habit. 



Position and localities. Hall obtained his material at the Normanskill 

 (Kenwood) ; besides this we have before us specimens from Glenmont, 

 N. Y. associated with N . gracilis, D i p 1 g r. f ol iac e u s, C 1 i- 

 macogr. b i c o r n i s, I ) i c r a n g r. f u r c a t u s, D i c r a n c g r. r a mosus; 



