1921 J Schmitt: The Marine Decapod Crustacea of California 35 



Key to the California Genera of the Palaemonidae 



I. Rostrum prominently toothed above only, about two-thirds as long as carapace, 

 pronouncedly convex above, armed with five to seven teeth, with one or two 

 small teeth below near tip; behind rostrum there is a median gastric spine. 

 An hepatic spine present. Mandible without palp. (Not known north of 

 San Diego Bay.) 



Urocaris, p. 37. 

 II. Rostrum prominently toothed above and below. No hepatic spine. 



A. Rostrum about as long as carapace, armed with six to ten teeth above, 



one or two of which are behind the orbit, and with two to four teeth 

 below. Mandible without palp. (Known only from San Pedro.) 



Palaemonetes, p. 36. 



B. Rostrum longer than carapace ; armed with seven to eight teeth above, 



one or two of which are behind the orbit, and with three teeth below. 

 Mandible with palp. (Not known north of San Diego.) 



Palaemon, p. 35. 



Genus Palaemon Fabricius 



Rostrum prominently toothed above and below. Carapace furnished with 

 antennal and branchiostegal spines, but without hepatic spine. Mandible with 

 three- jointed palp. 



Palaemon ritteri Holmes 



Palaemon ritteri Holmes, Proe. Calif. Acad. Sci. (2), 4, 579, pi. 21, figs. 

 29-35, 1895; Occas. Papers Calif. Acad. Sci., 7, 216, 1900; Rathbun, 

 H. A. E., 10, 29, 1904. 



Fig. 21. Palaemon ritteri; a, lateral view of carapace; b, mandible (after 

 Holmes). 



