752 AETHROPODA phylum vii 



Pephricaris Clarke (Fig. 1456). Carapace as in the last, but without the lateral 

 carinae. Margins provided with a single row of long recurving spines. Three or 

 four abdominal segments protrude beyond the carapace, the last two having a single 

 pair of long sjiines. Ujiper Devonian ; New York. 



Aristozoe Barr. (Bactrojms Barr.). Carapace with cephalic node well developed, 

 but without lateral carinae. But one abdominal segment known, and this is very- 

 long, cylindrical, with an intricate hinge at the articulation with the caudal spines. 

 Telson a long spine with a row of spinules on each lateral edge. Novak has shown 

 that of Barrande's three species, Aristozoe regina, Bactropus longipes and Geratiocaris 

 dehilis, the first rej^resents the carapace, the second the last abdominal segment, and 

 the third the telson of one form, A. regina. Devonian ; Bohemia. Species referred 

 to the same genus have been described from the Cambrian of North America and 

 Devonian of Germany and Russia. 



Orozoe and Callizoe Barrande are presumably allied to Aristozoe, Silurian ; 

 Bohemia. Zonozoe Barr. and Solenocaris Young are not Crustaceans. 



Eleutherocaris Clarke. Carapace elongate-subc^uadrate, truncate in front, incurved 

 behind ; rostrate (?). Broad, obscure nodes in the cephalic region ; lateral carinae 

 single, anterior and very short. Body segments unknown ; caudal plate with a 

 slender telson and cercopods of equal length. Surface of all known parts more or less 

 strongly tuberculated. Upper Devonian ; New York. 



Ptychocaris Novak. Valves elongate-subquadrate, posterior margin sloping or 

 slightly incurved. Ceijhalic region with a cluster of small nodes in front, and two 

 larger nodes behind. Lateral region with a single long sigmoid carina. Surface 

 striated with raised longitudinal lines. Abdomen and tail unknown. Lower 

 Devonian ; Bohemia. 



Elymocaris Beecher. Surface of carapace evenly convex, smooth, without lateral 

 carina ; hinge line long ; posterior margin convex ; cephalic 

 nodes obscure ; rostrum not observed. Abdomen with two ex- 

 posed segments ; caudal plate short, with broad convex, rapidly 

 tapering telson and two cercopods, setigerous on their inner 

 margins. Middle Devonian ; New York. Upper Devonian ; 

 Pennsylvania. 



Tropidocaris Beecher (Fig. 1457). Carapace with truncate 

 posterior margins ; ocular node well defined, other cephalic 

 nodes obscure ; rostrum narrow and ridged ; surface of valves 

 Fi(i. 1457. with several strong longitudinal carinae. Abdomen with two 



Trojndocans hicarmata exposed segments, which are sub -cylindrical and without 



Beecher. Chemung . . "^ 



Group ; Warren, Penn. spinules. Upper Devonian and Lower Carboniferous ; Penn- 



Carapace and rostrum, i/i qvlvania 

 (after Hall and Clarke). syivania. 



Emmelezoe Jones and Woodw. Valves of carapace elongate, 

 narrow, and with distinct ocular node ; other cephalic nodes wanting. Surface with 

 fine longitudinal raised striae. Abdomen unkno-wii. Sihtrian. 



Suborder D. RHINOCARINA Clarke. 



Carapace with a free rostrum and narroio median dorsal plate separated from the 

 valves by a straight or slightly curving hinge at each side. Ocular nodes clearly defined, 

 with a distinct optic pit at the summit. 



Family 1. Rhinocaridae Clarke. 



Valves articulated by interlocking at the single point ivhere they come in contact. 

 Abdominal segments two to three. Posterior margin of carapace concave and spined. 



