CRUSTACL'A 107 



Proetos canaliculatus. 



PLATE XX, KIi.s 10, 11; ixn PLATE XXIII, FIGS 



Proctus canaliculatus, II mi.. Descr. New Species of Fossils, etc., p. 73. 1861. 



Proetus canaliculatus, Hall. Kit' nth Rept. N. Y. State Cab Nat. lli>t . ].. 101. 1862. 



Pro'itus canaliculatus, Hail. Ill Devo: an Fi ssils, pi. xx, figs. 10, 11. 1876. 



The original of this species is a fragmenl showing the intra-sutural port ion 

 of the cephalon, and more complete material has not been observed, with the 

 exception of a few detached cheeks which may safely he regarded as belong- 

 ing to this form. 



The species is characterized by its violin-shaped glabella (genus Portia, Bur- 

 meister), constricted at the anterior angle of the eye. and broadly rounded on 

 the anterior extremity. Its length would he more than two-thirds the length 

 of the cephalon, and its width apparently somewhat less than one-third that 

 of the cephalon. 



The transverse furrows are indistinct upon the crust, hut appear to consisl 

 of three pairs and the accessory pair. A cast of the lower surface would 

 probably show a small anterior pair. The first pair visible is transverse, 

 and the posterior pairs are inclined backward. All the glabellar lobes are 

 taint. The occipital lohes are conspicuous; the occipital furrow narrow and 

 deep; the occipital ring moderately broad and flattened. The border is very 

 broad and tlat. and is grooved along the anterior limbus by two furrows, the 

 anterior of which is narrow and close upon the edge, the other is broad and is 

 separated from the frontal margin of the glabella by a rounded ridge Upon 

 the cheeks these grooves become shallower and reduced to two planes, the in- 

 terior and broader one horizontal, the anterior narrower and beveling. At the 

 genal angles the border is produced into moderately long and stout spines, 

 which are ridged upon the surface and minutely incurved at the tip. 



The eyes and palpebral lobes are comparatively large, the orbital ridge ele- 

 vated, the cheeks flattened at their summit below this ridge, abruptly curving 

 to the marginal and occipital furrow-. 



The surface is smooth upon the border, finch granulose upon the glabella, 

 and pustulose upon the flattened summits of the cheeks. 



