GRAPTOLITES OF NEW YORK, PART 2 I 59 



C a 1 y p t o g r a p t u s subr e tif or mis (pars) Spencer. Acad. Sci. St Louis. Trans. 



1S84. v. 4, pi. 4, fig. 2 

 Calyptograptus subretifonnis (p ars ) Spencer. Mus. Univ. State Mo. Bui. 



1884. v. 1, pi. 4, % 2 

 Dictyone m a p o 1 y m o r p h u m Gurley ms 



The Rochester shale at Middleport, N. Y. has furnished us a consid- 

 erable number of specimens of a form which by comparison with Gurley's 

 type has been found to be identical with the above cited species. The 

 latter has, as shown by the above given bibliography which is taken from 

 Gurley's manuscript, been partly described as D. tenellum and partly 

 as Calyptograptus s.u b re t if orm is. We insert here Gurley's 

 elaborate description of this species which is accompanied by two drawings 

 [pi. 3, fig. 5, 6] made under his supervision, the first of which, being cited 

 by Gurley in the manuscript, is to be considered as representing the type, 

 the other as a cotype. 



Polypary originally cyathiform, circular or flabellate on the rock, when 

 flabellate often evenly semicircular in the largest specimen seen, 85 mm in 

 diameter; originating in, and sessile upon a carbonaceous "disk," which in 

 one specimen is seen to have its walls riddled with pores. Branches meas- 

 uring 0.6 mm in width on the average, hardly ever as narrow as 0.3 mm (as 

 Spencer states them to average), 0.4 mm being with rare exceptions, the 

 minimum; and 0.8 the maximum. Branches varying equally in character, 

 being sometimes nearly straight, at others irregularly sinuous, and inoscu- 

 lating as in Desmograptus. Occasionally the adjacent margins of two 

 branches coalesce. The branches end in long drawn out, spikelike points. 

 Very often — usually in fact — shortly before their termination, they bifur- 

 cate U-like, the termination thus being forcepslike. This mode of ending 

 is quite characteristic of the species. Apparently this spikelike forking of 

 the branches may occasionally take place in the wall of the polypary below 

 the summit, and the spikes then seem to serve the same purpose as dissepi- 

 ments bracing the polypary. As the fossil usually lies on the stone, the 

 number of branches in 25 mm of width is exceedingly variable, generally 

 from distortion. In places where the polypary is evenly and smoothly laid 

 out and the meshwork perfectly regular, however, the number is about 22 

 (20-25) ne ar the base and about 25—30 at the periphery. The dissepiments 

 are of medium thickness (about 0.15—0.4 mm) and are either perpendicular 

 or highly inclined (say 45' 1 ) to the branches, and this combination in the 

 same specimen forms a striking feature of this species, a feature well shown 



