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NEW YORK STATE MUSEUM 



last in which the length exceeds the width of the anterior or 

 wider end. They are depressed and have faintly denned pleural 

 areas or fiattenings at the sides. Each is prolonged on either 

 side, at the posterior angle, into a short, striated spur, which 

 grows longer with each succeeding segment, those on the last 

 forming conspicuous pointed lobes. The first two segments 

 each carry on the dorsal side four triangular scales like those 

 of the preabdomen, the third, fourth and probably the fifth, 

 each two. the last none. This segment has a shallow notch 

 in the middle of the dorsal, posterior edge, marked on either 

 side by a small denticle, succeeded toward the sides by very 

 minute ones. The series of striations of the lobes continue up 

 the sides of the segment to its articulation with the preceding. 

 On the ventral portion of each ring segment is a shallow 

 posterior emargination fringed with lobelike teeth. Extending 

 forward from near either end is a curved rent, a pair sometimes 

 almost inclosing an irregular, oval area. 



The telson is very long, nearly equaling in length the rest 

 of the postabdomen. For a short distance from the anterior 

 end it contracts rapidly, then continues slender to the abruptly 

 rounded point. The edges are sharp and, from near the 

 anterior end, are marked by short, oblique incisions. The 

 dorsal surface is smoothly convex, the ventral has a flat topped 

 carina which begins near the proximal end and extends to the 

 tip. On the carina is a double row of pits like those bordering 

 the cephalothorax. 



The doublure, at its dehiscence in the axial line, equals in 

 width about one fourth the length of the cephalothoracic shield. 

 From this point it narrows toward the genal angles. 



The preoral appendages have not been observed. The endog- 

 nathites are robust and vary greatly in length, the first pair 

 being barely lon£ enough to reach the shield border, while the 

 members of the third clear it by fully three fourths their length. 

 The fourth pair is known only by a coxal joint and a basal por- 

 tion consisting of three joints. The first legs consist of seven 

 joints; the second and third each, of eight. In the first three, 

 ench joint from the third to the penultimate is provided with 



