1921 ] Schmitt: The Marine Decapod Crustacea of California 147 



A. Carapace not spiny on upper surface; rostrum short, simple, triangular. 



1. Carapace and legs much flattened and more or less hairy or pubescent ; 



lateral margins of carapace with a few small teeth or spines. 

 Anterior margin of ambulatory legs deeply incised, incisions 

 hidden by hairiness of legs. (Not known south of Monterey.) 



Eapalogaster, p. 148. 



2. Carapace not so flattened, moderately convex, somewhat roughened, 



granular on upper surface, slightly setose but not hairy; lateral 

 margins unarmed. Ambulatory legs subcylindrical, very sparsely 

 haired. (Not known south of Pacific Grove.) 



Oedignathus, p. 150. 



B. Carapace distinctly flattened and covered with numerous subequal 



spines; rostrum terminated by strong spines. Legs spiny, with long 

 hairs arising from tip of spines. (Not known south of Monterey.) 



Aeantholithodes, p. 152. 

 II. Abdomen segmented, and subdivided into more or less well calcified plates, 

 which are usually applied quite closely to the thoracic sternum; basal 

 (second) segment always provided with a pair of marginal and a pair 

 of lateral plates, and a median plate; plates either separated by sutures 

 or more or less completely fused with one another; abdomen quite 

 smooth or armed with more or less prominent tubercles or spines; occa- 

 sionally abdominal plates have a central membranous area. 



A. Abdominal plates with characteristic raised and rounded papillated 



edges enclosing a central membranous area; median and lateral 

 plates of basal (second) segment distinct. Ambulatory legs about 

 as long as greatest width of carapace. Outline of carapace prac- 

 tically forming an equilateral triangle; upper surface with two deep 

 pits within a triangular excavated area, surrounded by rounded 

 papillated tubercles. (Not known south of Monterey.) 



Phyllolithodes, p. 153. 



B. Abdominal plates without a central membranous area. 



1. Ambulatory legs shorter than the greatest width of the carapace, 

 usually much shorter. 



a. Carapace broadly oval, convex, smooth, and produced into lateral 



expansions, which completely conceal the ambulatory legs, 

 forming a large expanded dorsal shield. Basal (second) 

 abdominal segment entire. (Not known south of Monterey.) 



Cryptolithodes, p. 154. 



b. Carapace not so produced, more crab-like in appearance, more or 



less prominently tuberculated. 

 i. Outline of carapace practically forming an equilateral tri- 

 angle; with a deep semilunar fossa separating the smooth 

 hemispherical cardiac region from the other more or less 

 coarsely tuberculated regions of the carapace. Plates of 

 basal (second) abdominal segment distinct. (Not known 



south of Crescent City.) 



Rhinolithodes, p. 157. 



ii. Outline of carapace roughly pentagonal or hexagonal, very 



convex, roughened, with many close set, short tubercles 



and fewer more or less prominent subconieal tubercles. 



Basal (second) abdominal segment entire. (Not known 



south of Monterey.) 



LophoKthodes, p. 155. 



