CKAPTOrjTES OF NEW YOIIK, PART 1 



039 



St John basin, cited here under S t a u r o g r a p t u s d i c h o t o m u s [p.614], 

 have been referred to that genus. In the Deep kill beds we have two 

 new species termed B . p u s i 1 1 u s and B . 1 a ^3 av o r t h i , 



It is a remarkable fact that the genus Bryograptus, which in Sweden 

 and Enghuid is apparently restricted to the Upper Cambric beds^ and 

 which has also failed to be observed in. the Canadian Levis beds, corres- 

 ponding to the Deep kill horizon, persists here in the Tetragraptus beds 

 with two species, one of which (B. pusillus) is extremely rare, while 

 the othei- perfectly covers at least one layer and is also quite common as 

 a component of the typical Tetragraptus fauna on other rock surfaces of the 

 same bed. 



Bryograptus lapworthi sp. nov. 



Plate 5, figures 1-12 



Bryograptus sp. nov. Ruedemann. N. T. State Paleontol. An. Rep't. 1902. 

 p.556 



Description. The rhabdosome is suspended by a nema often relatively 

 long, and very thin. This has in several cases been observed to be 

 attached — in one case by means of 

 a little chitinous node [fig.l2] — -to 

 small chitinous blotches, supposed- 

 ly the remains of a primary disk. 

 The sicula is of medium size or 

 rather short (1 . '2 mm in the aver- 

 age). The first theca originates 

 close to the apex of the sicula, 



1 , j> ,1 (• , 1 1 ,1 f. Fig.47 Bryograptus lapworthi sp. nov. Young- 



aOOUt one lOUrtn Ot tne Jengtll of rhabdosome wUn fragment of primary disk. Obverse 



view. x6 



the sicula from the same [fig.47 |. 



This first theca produces the second one close to its own initial point and 

 both these primary thecae diverge from the sicula each at an angle of about 

 110", so that the average divergence between the proximal parts of the result- 



1 One exception, tliat of a species of B. raiiiosus var. cunibrensis on a 

 slab with Tetragraptus bigsbyi, is noted by Miss Elles [1898, p.472]. 



