308 Miss E. 31. Partridge — On Echinocaris Whidbornei, etc. 



either specimen; the cephalic swellings similar to those of -E". socialis 

 (Beecher). The thoracic portion of the valve possesses two ovate 

 tubercles, one (the smaller) parallel with the outer margin and 

 situated in the upper outer corner of the thoracic portion of the 

 valve ; the other is situated transversely, and found in the upper 

 dorsal portion near the hinge. Along the outer margin of the first 

 tubercle runs, parallel with the margin and towards the posterior 

 angle of the valve, a sharp, almost smooth carina ; at its upper end 

 it bends outward to the ventral margin of the valve. From the 

 other tubercle runs a second, nodose ridge, almost coinciding with 

 the dorsal line, and continued along the margin of the valve. In the 

 centre of the area enclosed by these two ridges is a longitudinal row 

 of minute nodes, ornamenting a third carina. The other elevated 

 portions of the valves possess also minute irregular tubercles, but 

 the outer carina is almost or quite free from these. Abdomen 

 composed of six visible segments (the telson being absent in our 

 specimens), the whole tapering, the posterior segments a little longer 

 than the anterior. The posterior margins of each segment are 

 ornamented with a number of small nodes, the anterior segments 

 possessing fewest of these. A few tubercles are also found on the 

 surface of the segments between the posterior and anterior margins. 



Measurements: Length of valves, 9-10 mm. ; greatest width of 

 a single valve, 4-7 mm. ; abdomen, 11 mm. long. 



This species much resembles E. socialis (Beecher), but the carapace 

 is much longer in proportion to its width. The outer carina also is 

 almost or quite smooth, and bends outward to the ventral margin of 

 the valve instead of fusing with the tubercle as in S. socialis. The 

 middle carina is also more prominent than in E. socialis. 



I am much indebted to Dr. Henry Woodward for kind assistance 

 and advice in the preparation of this note. 



Eeferences. 



1884. C. E. Beecher, " Ceratiocaridse from the Chemung and AVaverley Groups at 

 "Warren, Penns34vania " : Eeport of Progress PPP, Second Geol. Surv. 

 Pennsylvania. 



1888. J. Hall & J. M. Clarke : Geol. Surv. State of New York, vol. vii, 



pp. 166-181 and pis. xxviii-xxx. 



1889. T. Eupert Jones & H. "Woodward, " On some new Devonian Fossils " : 



Geol. Mag., Dec. Ill, Vol. VI, No. IX. 

 1899. T. Eupert Jones & H. "Woodward, "Contributions to Fossil Crustacea": 

 Geol. Mag., Dec. IV, Vol. VI, No. IX. 



EXPLANATION OF PLATE XVII. 



Bchinocaris from the Marwood Beds, Sloley Quarry, near Barnstaple. 



Fig. 7. — Echinocaris Whidbornei (Jones & "Woodward). Partridge Collection, x 2. 

 Fig. 8. — Echinocaris Sloliensis, n.sp., right valve of carapace. Coomcirasw&.my 



Collection, x 2. 

 Fig. 9. — Echinocaris Sloliensis, n.sp., another specimen, more complete. Partridge 



Collection, x 2. 



