Species of the Chkmuno Gkouk 129 



the reticulum produced by the sixth Hcries of bandH. The presence of this 

 series produces 1024 divisions in each primary (puidruh;. Tlie conspicuous 

 ridges of the lateral surfaces extend over the broad, sulxtonical base, the ver- 

 tical bands converging at the apex and the horizontal bands l>eing distinctly 

 concentric. The basal cone is shown in two examples, in one of which it is 

 attached to a portion of the cup and is extremely compressed laterally. In 

 the other, such distortion as it has undergone is in the opposite direction, 

 vertical rather than lateral. The latter specimen represents a cup with a 

 diameter t)f about 80 mm., bears a decidedly eccentric ajKix and shows the 

 characteristic coaree and minute reticulation of the surface. The depth of 

 this cup is 17 mm. 



 Dimensions. All specimens of this species observed are of about the 

 same size. The original example, which is nearly entire in length though not 

 retaining the basal cone, is 135 mm. long and 64 mm. wide. Another entire 

 specimen has a length of 120 mm. and a width at the aperture of 70 mm. 



This species is readily recognized, even in the absence of its basal 

 diaphragm by its stout, cylindrical shape and coarse primary reticulation. It is 

 closely allied to T. Handalli though rather less stout. The characters of the 

 latter species are not, however, so well known. 



Localities. In the upper beds of the Chemung group, at Little Genesee, 

 Alma and Wellsville, Allegany county, at Ischua, Hinsdale and Olean, Catta- 

 raugus county, and Chemung narrows, Chemimg county. 



Thtsanodiotta Randalli, Hall (sp.). 



Plate xxiv. Fig. 12. 



1890. Dictyophyton Randalli^ Hall. Ninth Ann. Kept. N. Y. State GeoL, 

 p. 57 ; Forty-third Ann. Kept. N. Y. State Museum, p. 259. 



The specimen upon which the oiiginal description of this species was 

 based, is the upper portion of a flattened, once cylindrical cup whose surface 

 is covered with low longitudinal and horizontal ridges which form quadrules 

 measuring about 17x'il mm., each of these being subdivided by secondary 

 ridges of nearly the same pi-ominence as the first. The subordinate c'uicella- 

 tion of the surface is very fine. At the upper extremity of the specimen where 

 the apertural margin is retained there is some indication of a continuation of 

 the vertical spicular bands beyond the edge of the cup. The length of the 

 specimen is 90 mm.; its apertural diameter is 78 mm. This form is very 

 closely allied to T. riidis, though present evidence indicates that the cup ^vas 



