Monograph of the Crustacea of the Cmcinnati Gi'oup. 143 



Length of cephalic shield, exclusive of the posterior lateral spines, 

 35-lOOth inch, including do., 60-lOOth inch; breadth, 67-lOOth inch ; 

 anterio-posterior diameter of eyes, 12-1 00th inch ; height of same on 

 outer side, 8-lOOth inch. 



Thorax with eleven segments, axial lobe strongly convex, lateral 

 lobes flattened, pleurie curved backward and obtusely pointed at their 

 extremities ; gradually tapering from the neck segment to the pygid- 

 ium. Length of thorax, 6-lOth inch ; greatest breadth, 7-lOth, and 

 tapering to 5-lOth inch. 



Pygidium sub-trigonal, rather depressed, as Avide as long, very nar- 

 rowly rounded or almost sub-angular behind ; the posterior exti-emity 

 being curved a little upward ; mesial lobe depressed, but a little more 

 convex than the lateral, and of about the same breadth, or slightly nar- 

 rower at the anterior end, and narrowing to the posterior extremity, 

 which does not reach the margin, composed of about thirteen distinct 

 seo-ments, and two or three other very small, obscure ones behind these ; 

 lateral lobes separated from the mesial lol5e by moderately distinct fur- 

 rows, and sloping off gently, ^vith slight convexity of outline, to the 

 lateral and posterior margins, showing each, about thirteen segments, 

 which are not fuiTOwed, and extend very nearly, but not quite, to the 

 margin, the smaller posterior ones being directed very obliquely back- 

 ward ; surface showing rather fine, irregular, scattering granules. 



Length of pygidium, tVo*^^ "^^^^ > breadth, f^fo^^"' inch. 



Found at Cincinnati, from 300 feet above low water-mark to near 

 the top of the hills. Extremely rare. Dr. R. M. Byrnes has a fine 

 specimen, rolled up, and Prof. Harper has a fine specimen, extended. 



Dcdmanitcs hreviccps — (Hall, 1866). 



Body broadly ovate in general form, its greatest width across the 

 base of the cephalic shield. Head sub-crescentiform, the anterior mar- 

 gin very slightly produced in front of the glabella. Frontal lobe of 

 glabella transversely elliptical, the breadth nearly twice as great as the 

 length ; separated from the anterior lobe by deep, narrow furrows- 

 Anterior lobe transversely subovate, prominent ; middle and posterior 

 lobes obsolete, occipital ring narrow, distinctly defined. 



Eyes very prominent, with five lenses in the central, vertical range, 

 but the number of vertical ranges can not be determined ; palpebral 

 lobe depressed. The outer border of the movable cheeks is thickened 

 and rounded, and the space between the border and the eye depressed- 

 The posterior spines long and broad, reaching to the sixth thoracic seg- 

 ment. 



