16 



North American Palaeozoic Crustacea. 



Belli, Hall & Clarke, 1888 ; Pal. New York, vol. 7, p. 194. 

 carbonarius, Meek & Worthen, 1870 ; Proc. Acad. Nat. Sci. Phila., vol. 22, 

 p. 55. Coal Measures. 



carbonarius, id., 1873; Geol. Survey Illinois, vol. 5, p. 618, pi. 32, fig. 1. 

 carbonarius, White, 1884 ; 13th Rept. Dept. Geol. Nat. Hist. Indiana, 



p. 178, pi. 39, fig. 2. 

 Neptuni, Hall ; see Mesothyra Neptuni. 

 Dolichopterus (subgenus Euj-ypterus) , Hall, 1859 ; Pal. New York, vol. 3, p. 414*. 

 inacrocheirus. Hall, 1859 ; Pal. New York, vol. 3, p. 414*, pi. 83, fig. 1 ; 

 pi. 83 a, fig. 1. Waterlime. 



Dolichocephala, Claypole, 1883 ; Proc. Am. Philos. Soc, vol. 21, p. 236. 



Lacoana, id., p. 236, plate. Catskill. 



Referred to Sti/lomij-us excelsior, 

 Echinocaris, Whitfield, 1880; Am. Jour. Sci., 3d series, vol. 19, p. 34. 



Diagnosis. — Carapace bivalviilar, eauli valve 

 oblique by subovate in outline ; hinge-line 

 straight and shorter than the greatest length 

 of the shield. Anterior extremities slightly 

 gaping, posterior extremities somewhat pro- 

 duced, incurved, or truncate. Rostrum ab- 

 sent or not observed. The cephalic and 

 anterior portion of the thoracic area marked 

 by various regularly and symmetrically ar- 

 ranged nodes, two of which bear the optic 

 spots. Nuchal furrow more or less distinct. 

 The thoracic portion of each valve bears one 

 or two longitudinal, somewhat curving lateral 

 ridges or carinae. Abdomen naked, composed, 

 so far as known, of 6 somites, which are 

 furnished with short spinules or prickles on 

 their dorsal surface. Caudal plate short and 

 produced into a stout telson. Lateral spines 

 or cercopods narrow and longer than the 

 telson. (Hall & Clarke, Pal. New York, vol. 7, p. liv.) 

 condylepis, Hall & Clarke, 1888-, Pal. New York, vol. 7, p. 173, pi. 29, 

 figs. 14-17. Chemung, 



multinodosa, Whitfield, 1880 ; Am. Jour. Sci., 3d series, vol. 19, p. 38, 

 pi. o, fig. 8 (plate only with special author's ed.). Erie shales, 



multinodosa, Packard, 1882; Am. Naturalist, p. 952, fig. 10. 

 multinodosa, Packard, 1883 ; 12th Rept. U. S. Geol. Survey Territories, 



p. 451, fig. 71a. 

 multinodosa, Beecher, 1884 ; 2d Geol. Survey Pennsylvania, vol. PPP, p. 5. 

 multinodosa, Etheridge, Woodward & Jones, 1S85 ; 3d Rept. Comm. Fossil 



Phyllopoda Pal. Rocks, p. 35. 

 multinodosa, Hall & Clarke, 1888 ; Pal. New York, vol. 7, p. ISO, pi. 29, 

 figs. 18, 19. 



