CALIFORNIA STALK-EYED CRUSTACEA. 113 



Legion LITHODINEA. 



Carapace broad, often resembling that of the Brachyura. Rostrum 

 generally well developed. Third ambulatory legs subequal to the preced- 

 ing pair; last pair feeble, chelate, and folded in the branchial chamber. 

 Sternum wide. Abdomen bent under the thorax; in the male it is devoid 

 of appendages, but in the female the first segment may bear a small pair, 

 and, each of the four following segments often has an appendage only on 

 the left side. 



KEY TO THE GENERA OF Lithodinea. 

 Carapace smooth and produced laterally into two wings, which 



conceal the ambulatory legs Cryptolithodes. 



Carapace not so produced. 



Carapace devoid of spines or tubercles on the upper surface. 



Carapace much flattened, hairy Hapalogaster . 



Carapace not much flattened; acicle curved (Edignathus. 



Carapace not much flattened; acicle straight Dermaturus. 



Carapace with spines or tubercles above. 



Carapace with deep pits above Phyllolithodes . 



Carapace not deeply 'pitted. 



Abdomen membranous. Carapace spiny. .. . Acantholithodes. 

 Abdomen furnished with calcareous plates. 



Carapace tuberculated Lopholithodes. 



Carapace spiny Lithodes. 



Genus Hapalogaster Brandt. 



Carapace flattened and marked with chitinous, uncalcified lines; lateral 

 margin with teeth or spines. Last joints of the external maxillipeds 

 dilated. Chelipeds depressed, very unequal; hands more or less trigonal, 

 moving horizontally. Ambulatory legs depressed. Abdomen soft, loosely 

 inflexed, the basal segment with a transverse, calcareous plate on either 

 side. 



Type.- H. Mertensii BRANDT. 



Hapalogaster cavicauda St. 



Hapalogaster cavicauda STIMPSON, Ann. N. Y. Lye. Nat. Hist., Vol. VII, 

 1860, p. 81, PI. I, fig. 7; Proc. Acad. Nat. Sci. Phila., 1858, p. 232. 

 SCHALFEEW, Melan. biol., Tome XIII, p. 326, du Bull. Acad. imp. sci. 

 St. Petersb., Tome XXXV, p. 332. BOAS, Vid. Selsk. Skr., 6 Roekke, 

 Natur. og Math., Afd. 1, 2, 1894, p. 194, PI. VI, fig. 200. BOUVIER, 

 Ann. Sci. Nat. (7), Tome XVIII, 1894, p. 166, PI. XI, fig. 2, and PI. 

 XIL, figs. 1, 15, 27 and 29; Ibid. (8), Tome I, 1896, p. 2, et seq. 



