Neiu Species and A'ew Slriiclunxl Paris of Fossils. S3 



Pk()T().scoi,I':x macni s, n. sp. 



Plate /, /vi,'. 5, Haliiral size : P/]^ . 6, niag7iificd lico diatnelers. 



This species is larger tlian any defined by Mr. ITlrich, but 

 otherwise very much like P. ornalKs. His diagnosis of the 

 genus is limited, and no idea of the character or substance of 

 the shell is indicated, and, therefore, in attempting to describe 

 this species there will necessarily be a commingling of generic 

 and specific characters, to a certain extent. 



The test is very thin and exceedingly fragile. If one could 

 conceive of a crinoid column composed of very thin plates and 

 possessed of a thin epidermal coating, which it could shed, and 

 such coating could become fossilized and more or less com- 

 pressed, it would be a very good ideal representation of the 

 tests in this genus. Generally they are finely granular and 

 black or brownish black, but, sometimes, they have a grayish 

 color something like that of a crinoid, but without the crystal- 

 line structure. They are not any thicker than the coating of 

 a Graptolite, and do not have the same .shining black color or 

 corneous texture. They occur in soft blue shale or semi-in- 

 durated mud. 



As above remarked, the}' appear as compressed, elongate, 

 cjdindrical bodies, composed of very thin segments. In the 

 species under consideration, the length of about ten segments 

 will equal the greatest diameter of the body, in its compressed 

 condition. Each segment is ornamented with a single row of 

 six or eight papilke. All specimens observed are curved more 

 or less, and all taper a little toward one end. The length of 

 the specimen, part of which only is illustrated, is one and three- 

 fourths inches, and the larger end is not complete, and it is 

 doubtful about the completeness of the smaller end. 



That these bodies are not crinoid columns, in any state of 

 mineralization, the following evidences are offered: 



1. No crinoidal matter enters into the substance of the test. 



2. We know of no crinoid columns, in any group of rocks, 

 having undergone such destruction and mineralization as to 

 leave only the representation of the extreme outer coating, in 

 a fossil condition. 



3. We know of no crinoid columns in the group of rocks, 



