PRO.] 



CRUSTACEA. 



563 



has apparently been pressed smooth. 

 Type P. septemnotatus. 



_; alternans, Owen, 1852, 

 Jour. Geo. Soc., vol. 

 8, pi. 14, Potsdam 



latus, Owen, 1852, Jour. 

 Geo. Soc., vol. 8, pi. 

 11, Potsdam Gr. 



lineatus, Owen, 1852, 

 Jour. Geo. Soc., vol. 

 8, pi. 13, Potsdam 

 Gr. 



logananus, Marsh, 

 1869, Am. Jour. Sci. 

 and Arts, 2d ser., 

 vol.48, Potsdam Gr. 



multinotatus, Owen, 

 1852, Jour. Geo. Soc., 

 vol. 8, pi. 12, Pots- 

 dam Gr. 



octonotatus, Owen, 

 1852, Jour. Geo. Soc., 



dam Gr. 



septemnotatus, Owen, 

 1852, Jour. Geo. Soc., 

 vol. 8, pi. 9. Pots- 

 dam Gr. 

 , PROTOBALANUS, Whit- 



FiG. 1048. Protich- fl ,, -i Qee V> i vr v 



nites septemnota- field, 1888, Pal. N.Y,. 

 tus. vol. 7, p. Ixii. [Ety. 



protos, first ; Bala- 

 nus, genus.] Shell ovate about the 

 basis ; composed of 12 plates of which 

 the carina is largest and most elevated ; 

 rostrum small ; lateralia five on each 

 side ; radial areas between the lateralia 

 broad. Type P. hamiltonensis. 

 hamiltonensis, Whitfield, 1888, Pal. N. Y., 

 vol. 7, p. 209, Ham. Gr. 



PROTOCARIS, Walcott, 1884, Bull. U. S. Geo. 

 Sur., vol. 2, p. 283. [Ety. protos, first; 

 karis, shrimp.] Carapace without evi- 

 dence of a dorsal suture, rounded on 

 the dorsal line, and bent downward on 

 the sides ; no rostrum ; body many 

 jointed, 31 segments extending out 

 from beneath the carapace, the last 

 segment broader than the preceding, 

 and terminating in two spines. Type 

 p. marshi. 



marshi, Walcott, 1884, Bull. U. S. Geo. 

 Sur. vol. 2, p. 283, Georgia Gr. 



PROTOLIMULUS, Packard, 1886, Mem. Nat. 

 Acad. Sci., p. 150. [Ety. protos, first ; 

 Limulus, a genus.] Cephalothorax 

 large, subsemicircular ; genal angles pro- 

 duced ; cephalic appendages small ; 

 terminal segments of the posterior mem- 

 bers f oliaceous ; abdomen composed of 

 six (?) segments, including the large 

 caudal spine. Type P. eriensis. 

 eriensis, Williams, 1885, (Prestwichia 

 eriensis,) Am. Jour. Sci. and Arts, 3d 

 ser., vol. 30, p. 46, Chemung Gr. 



PROTOTYPUS, Walcott, 1886, Bull, U. S. Geo. 

 Sur., No. 30, p. 211. [Ety . protos, first; 

 typus, type.] Body ovate ; head broad, 



semicircular; glabella large, sides par- 

 allel, rounded in front, no furrows; 

 frontal limb narrow, in front of the 



FIG. 1049. Protocaris marshi. 



glabella and bordered ; fixed cheeks 

 crossed in front of the eyes by an ocular 

 ridge ; eyes large, reniform ; occipital 

 ring narrow ; movable cheeks curved 

 on the outer margin and ^terminating 



FIG. 1050. Prototypus hitclicockl. 



in spines; facial suture passing very 

 little outward from the eye to the an- 

 terior margin, which it cuts at nearly 

 right angles ; behind the eye, it passes 

 obliquely outward and backward, with 



