has its sides deflected. The space between the front of the ghi- 

 bella and the base of the projection is somewhat depressed. 



The pygidium is obtusely triangular, with the front greatly 

 arched in uncrushed specimens, but this character seems to be 

 confined to the medium-sized specimens ; the larger forms are 

 not so much arched, and correspond in this respect to typical 

 pygidia of C. hlumenbaehii. The axis occupies along the anter- 

 ior border about one-third of the width of the tail, and gradually 

 tapers posteriorly into an obtuse point ; it is marked with about 

 eight or nine articulations, the anterior one being slightly arched 

 forwards, but the others are extended almost straight across it. 

 The dorsal furrows are well defined. The pj„ ^ 



lateral lobes are marked with five pairs of ribs, 

 four of wliich are grooved and double half-way 

 u\) ; they are contracted along tne dorsal fur- 

 rows, but widen out laterally. The ribs curve 

 downwards and backwards, and are separated caiume,,e rosimta 



V 1 J.I 1 11 1 (. T Vogdes. The pygi- 



irom eacli otiier by well-denned grooves, the dium usually foim.i 



, , . . "-, c- .1 iissociated with the 



last pair unite and form a ridge extending i^fa^i- 

 around the posterior termination of the axis. 



Geological Position. — Clinton Group, Taylor's Ridge, near 

 Catoosa Station ; and also at Dug Gap, Georgia. 



Among the trilobite specimens which 1 have collected in 

 Georgia, there arc three movable cheeks and one pygidium 

 showing a strong reseml)lance to the same parts of Calymene 

 Clintoni as figured l)y Prof. Hall in Pal. N. Y., vol. ii, pi. 66 a, 

 fig. 5. These fragments were found associated with two gla- 

 bellas, having characteristics not shown by the illustrations of 

 the species Just referred to ; therefore, for the purpose of com- 

 parison, I carried the speciihens to the American Museum, and 

 through the courtesy of Prof. Whitfield was enabled to study 

 the trilobitcs found in the Clinton Group of New York. The 

 Georgia forms are almost identical with those of New York, but 

 show some variations from the typical C. Clintoni ; 1 shall, 

 therefore, descri!)e these fraLnnents. 



