NOTES ON PALEOZOIC CRUSTACEANS 95» 



dimensions and tlie ornament of its last segment and caudal 

 spines, there is a distinct similarity to the latter. 



In form of carapace there is close resemiblance to C. s t j g i a 

 Salter (Ludlow, Lesmahago, etc.) but this is not continued to 

 the abdomen and tail. The same exipreseion is found in the 

 O. acuminata Hall of the waterlimes above the gypsum 

 (Rondout waterlimes) and one may well infer the probable iden- 

 tity of the English species with the American C. a c u m i n a t a. 

 Into the same category falls the O. m o n r o e i Whitfield from 

 the upper Siluric waterlimes near Waubeka (Wis.) a most in- 

 teresting form in which Prof. Whitfield has determined the ap- 

 pendages, intestinal canal and mandibles. 



Emmelezoe decora sp. nov. 



PLATE 2, FIGURES 4-11; PLATE 3, FIGURES 1-4 



Generic characters. When McCoy introduced his genus> 

 C er ati o c aris^ he based hi® conception on two species, O. 

 solenoidee and O. ellipticu® McCoy, both from the 

 upper Ludlow. The former is known today, even after the ex- 

 haustive investigation of these fossils by Jones and Woodward, 

 only by its long narrowly pod-shaped carapace, so markedly dis- 

 similar from the forms to which the name Ceratioc a r i s 

 is currently applied that we can not fail to surmise a different 

 conistruction of the generic term when the other parts of the type 

 species become known. C e r a t i o c a r i s e 1 1 i p t i c a , Mc- 

 Coy's second species, has been taken by Jones and Woodward as 

 the basis of their genus Emmelezoe, because of the pres- 

 ence of a well defined ocular tubercle. The species, too, and its 

 congeners, E.cras si striata, E. maccoyiana, E. 

 t e n u i iS t r i a t a , bear a decided linear ornament, which is 

 moisft pronounced in E. c r a e s i s t r i a t a. This is an upper 

 Ludlow species and with it our own form, the only American rep- 

 reeentative of the genuiS known, is most closely allied. 



^An. and mag. nat hist. 1849. 4:413. 



