CRUSTACEA— MALACOSTRACA. 389 



1908. Rathbun, Mary J. Descriptions of Fossil Crabs from Cali- 

 fornia. Proc. U. S. National Museum, Vol. 35, pp. 341-349, pis. 

 XLV.-XLIX. 



See also in faunal works, section on Crustacea (Cretacic and Tertiary), 

 viz.: California Pal., I. -II. ; Maryland Survey reports, Pliocene and 

 Pleistocene ; New Jersey Palaeontology, Vol. IV., Weller ; Proc. U. S. 

 Nat. Museum, White; Wilkes Exploring Expedition, Dana; and for 

 structural and systematic detail : Bronn's Klassen und Ordnungen des 

 Thierreichs. Crustacea, by Gerstaecker and Ortmann. 



Suborder Macrura Latreille. 



{Prawns, Shrimps, Lobsters, Crayfish, etc.) 



Abdomen at least as long as the cephalothorax ; last pair of 



pleopoda forming with the telson a powerful five-bladed caudal fin. 



Antennae mostly very long. Third pair of maxillipeds long and 



slender, not completely covering the preceding ones (Fig. 1692). 



Fjg. 1692. Alpheus nigro-spinatus Rankin. A modern prawn from the Bahamas.- 

 The figure shows the external organs of one side, i. e., the inner antenna with double 

 flagellum, the outer with a single flagellum, the long third maxilliped, the large claw, 

 or first pereiopod, the slender chelate second pereiopod, with the carpus five-jointed 

 (one long and four shorter joints) ; the third, fourth and fifth pereiopods ending in 

 spines (4th one missing) ; the first five pleopoda, and the caudal fin, (After Rankin, 

 New York Acad. Science Annals.) 



XVIII. LiNUPARUs Gray. 

 Cephalothorax cylindrical ; carapace thick and rigid ; without 

 rostrum, and with three longitudinal ridges ; pereiopods of six seg- 

 ments only and non-chelate. Cretacic-Recent. 



31. L. vancouverensis Whiteaves. Cretacic. 



Longitudinal ridges low, angular and tuberculous or spinose, 



the median one thicker and more obtuse than the lateral ones ;: 



