igo 



NEW YORK STATE MUSEUM 



At Stockport the variety is associated with X . gracilis, 

 Dicranogr. furcatus, C 1 i m a c o g r. parvus and D i p 1 o g r. 



f o 1 i a c e u s ; at Glenmont with D i c e 1 1 o g r. sextans, Dicranogr. 

 ramosus and Climacogr. b i c o r n i s. 



Nemagraptus exilis (Lapworth) var. linearis nov. 



Plate 17, figures 10-12 



Description. Rhabdosome consisting of two main stipes and a small 

 number of secondary branches at the distal ends of the former. The main 



stipes are nearly straight, attain 

 a length of 40+ mm and diverge 

 in the compressed material at an 

 angle that varies between 240° 

 and 280 , but most frequently 

 and typically is about 270 . 

 Their width is about .15 mm 

 at the center and has not been 

 seen to increase beyond .3 mm, 

 the stems appearing as uni- 

 205 formly thin lines. The length 



of the secondary branches is 



Fig. 204, 205 Nemagraptus exilis var. linearis nov. 

 Enlargements (x 5 ) of types [pi. 17, f. 12] not knOWIl, their width IS UOt 



greater than that of the main stipes and they are but 1.2 mm apart. The 

 sicula is 1 mm long, very conspicuous by its position, and furnished with a 

 straight apertural spine. The primary thecae originate about one third 

 from the apex of the sicula and diverge from it near its center, assuming 

 opposite, horizontal directions. They bear spines just below their apertures. 

 The upward flexure of the main stems takes place on either side with the 

 succeeding theca. - The thecae are very slender, six times as long as wide, 

 overlap but very little (about y 5 their length), have a small angle of incli- 

 nation ( io u ) and number 7 to 9 in 10 mm in the main stipes and 8 to 10 in 

 the secondary branches. The apertural parts are slight!)' introverted. 



Position and localities. This specie's is most common in one layer 



