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Ortmann — Crangopsis vermiformis. 283 



Art. XXXI. — The systematic position of Crangopsis vermi- 

 formis (Meek), from the Subcarboniferous rocks of Ken- 

 tucky ; by Arnold E. Ortmann, Ph.D. 

 IO 



In 1872 and 1875 F. B. Meek described* a peculiar Crus- 

 tacean from the lowermost Subcarboniferous rocks (base of 

 Waverly series) near Danville, Ky., under the name of Archceo- 

 caris vermiformis, but owing to the imperfect condition of 

 his specimens he did not express any opinion as to the sys- 

 tematic position of this fossil. The Museum of Geology of 

 Princeton University possesses quite a number of specimens of 

 this form, which were collected by M. Fischer at or near the 

 same locality (Boyle Co., Ky.), and which are also for the most 

 part poorly preserved. Yet a few specimens are better, and 

 one of them shows clearly a peculiar feature which enables us 

 to make out its approximate systematic position. 



Previously, Crustacean remains closely resembling Meek's 

 species have been reported by Salterf from the Subcarbon- 

 iferous (Mountain Limestone) of Scotland under the name 

 Palceocrangon socialis, the generic name being subsequently 

 changed into Crangopsis Salter,;]: in order to prevent confusion 

 with Paloeocrangon Schau roth. Salter places his fossils among 

 the Macrurous Decapods, considering the presence of a cara- 

 pace, of seven distinct abdominal segments, and of caudal 

 swimmerts as conclusive. These three characters are all that 

 is known of Crangopsis, and Archceocaris of Meek shows 

 exactly the same ; there is nothing that should induce us to 

 separate generically the American from the Scotch fossil. 

 Accordingly, we should consider Archwocaris as a synonym of 

 Crangopsis, and the American species should be called Cran- 

 gopsis vermiformis (Meek). The three characters which 

 induced Salter to place his genus among the Decapods are not 

 sufficient to warrant the correctness of this position. On the 

 contrary, these three characters are present, among the Mala- 

 costraca, in the same combination also in the living orders of 

 the Stomatopoda, Euphausiacea, and Mysidacea,% and we can- 

 not make out the proper position of these fossils according to 

 our present knowledge. From one specimen however in the 

 Princeton collection (Mus. No. 1597 c ) we learn another very 

 important character. 



*Proc. Acad. Philad., 1872, p. 335; Geol. Surv. Ohio, Palaeont., ii, 1875, p. 321, 

 pi. 18, fig. 1. 



f Trans. Roy. Soc. Edinburgh, xxii, p. 394 ; Quart. Journ. Geol. Soc. London, xvii, 

 1861. p. 533, fig. 8. 



tSee Zittel. Handb. Palaeont., ii, 1885, p. 682. 



§ Compare Boas, in Morpholog. Jahrb., viii, 1883. 



