Contributions to Invertebrate Palseontologxj. 571 



Palaeopalaemon ]Vevrl>erryi. 



Plate XII, figs. 19-21. 



Paheopalcemon Newherryi Whitfield, Am. Jour. Sci. and Arts, 3d series, vol. 19, 

 p. 41,1880. 



Body slender, the carapace forming a little more than one third of the entire 

 length, higher than wide, narrowed anteriorly and truncate behind ; being 

 longer below than above ; median line carinate, with a second carina on each 

 side a little below the crest ; anterior eni not rostrate but obliquely truncate, 

 and sloping rapidly backward above the truncation, forming, when looked 

 upon in front, a narrow elongated shield-shaped and slightly depressed area, 

 obtusely pointed above and rapidly widening at the base, the lateral carin?e 

 rising from the lower angles ; lower posterior angles rounded, basal margins 

 gently curved throughout and bordered by a narrow thread-like band with a 

 narrow groove within it. Abdomen moderately robust, highly arched along 

 the dorsal line, the pleura curving inward below, giving a cylindrical form. 

 Pleura broadly rounded at their extremities on the anterior face, but slightly 

 angular on the posterior corners ; posterior margin of the segments strongly 

 arching forward on the back. Telson elongate-triangular, a little less than 

 twice as long as wide, somewhat angular above and marked by a central ridge 

 below, and by a backward curving transverse ridge across the widest part. 

 Caudal flap large, forming a triangular plate on each side, the first and second 

 joints short, subtriangular ; marginal plate of the flap thickened, narrow, and 

 elongate, central plate narrowly triangular, a little longer than wide ; third 

 or inner plate of equal length with the second, and a little wider than the 

 marginal one ; the three combined as one, being apparently anculosed at their 

 margins to form a solid piece. Antennae very strong, the first joint half as 

 long as the thorax, slightly swollen in their lower half, and flattened on the 

 under side ; the other portions unknown. Thoracic limbs very slender and 

 only of moderate length, the second joint laterally compressed, making the 

 height nearly double the width ; other joints apparently cylindrical. Abdomi- 

 nal limbs known only by their second (?) joints, which appear to be triangular 

 in form, widening below, flattened and plate like in character or slightly con- 

 vex on the anterior face. (In one case only a single thread-like appendage 

 can be seen as if projecting from the outer lower angle.) 



Surface of the carapace marked by very fiiie tortuous and interrupted, 

 raised lines, strongest anteriorly and running obliquely upward and back- 

 ward ; also by a single, slender, distinct, raised ridge, extending more than 

 one-fourth the length of the carapace, originating at the lower anterior angle, 

 and passing upward and backward, with a bifurcation at the anterior third of 

 its length. Surface of the abdomen essentially smooth. Caudal flaps marked 

 by impressed lines, increasing in number and fineness from above downwards. 



The following species is introduced for comparison with Echino- 

 caris. 



