470 NEW YORK STATE MUSEUM 



Non Retiolites venosus Spencer. Mus. Univ. State Mo. Bui. 1884. p. 16; 



pi. 1, fig. 2 

 Non Retiolites venosus Miller. N. Am. Geol. & Pal. 1889. p. 202, fig. 



214 



Description. Rhabdosome file-shaped, with rounded sicular extremity 

 (.5 mm wide), whence it grows very regularly and gradually in a length of 

 23 mm to a width of 3 mm to 3.5 mm. From that point its margins remain 

 subparallel. The antisicular extremity has not been observed. The sec- 

 tion is depressed elliptic, the lateral faces being gently convex, the frontal 

 faces narrow and straight. The total length attained by the rhabdosome 

 has not been observed ; the longest fragment seen measured 34 mm. The 

 sicula has not been observed ; the thecae, as indicated by the parietal 

 ledges, number 10 to 14 in 10 mm. They are inclined at an angle of 50 , 

 their apertures are rectangular, and approximately parallel to the axis of the 

 rhabdosome ; their lateral margins concave, the upper and lower margins 

 convex and much thickened. The nemacaulus has not been observed. 



Position and locality. The species is thus far only known from the 

 Clinton beds in the gorge of the Genesee river below Rochester, X. Y. 

 Hall recorded it from the black layer in the green shales in association with 

 M o n o g r . clintonensis. Mr H. C. Wardell of this office has also 

 obtained some pyritized specimens from the same shale. 



Remarks. The pyritized specimens are entirely smooth and their sur- 

 face exhibits no trace of the network of fibers, thereby indicating that the 

 exterior perisarcal layer completely covered the meshes of the second layer, 

 leaving only the parietal ledges exposed to a point near the median line of 

 the lateral faces, where they curved gently inward to join one of the 

 ''virgulae" [.swpl. 29, fig. 7, pi. 31, fig. j\. 



Upon one of the two pyritized specimens there appear along the 

 median line several low depressions surrounded by low ringwalls, a feature 

 which might suggest that the species was an American representative of 

 the interesting European genus Stomatograptus Tullberg. Holm (dot- 

 lands Graptoliter, 1890) has pointed out that the two genera differ also in 



