112 ORTMANN — AFFINITIES OF CAMBARUS. [April 13, 



d 2 Sexual organs with tips crossed, the outer directed inward, the 

 inner outward. C. (Faxonius) indianensis Hay. 



c 2 Sides of carapace spinose, several spines behind cervical groove, and 

 spines on the hepatical region. Tips of sexual organs crossed. 



C. (Faxonius) limoszts (Raf. ). 



2. Section of C. propinquus (see p. 108). 



1. Group of C. propinquus (see p. 109). 



<?j Sexual organs reaching to the third pereiopods, with or without shoulder. 



b x Rostrum with or without median keel. Sexual organs without shoulder 



on anterior margin. C. {Faxonius) propinquus Gir. 



b 2 Rostrum without median keel. Sexual organs with shoulder on anterior 



margin. C. (Faxonius) obscurus Hag. 



a 2 Sexual organs reaching to the second pereiopods, without shoulder. 



C. (Faxonius) erichsonianus Fax. 



2. Group of C. rusticus (see p. 109). 



a x Rostrum with marginal spines. Carapace with a lateral spine. 



b x Margins of rostrum concave. Sexual organs reaching to the second perei- 

 opods 

 c x Tip and marginal spines of rostrum bent upward. Fingers of chela 

 gaping only at base. C. (Faxonius) rusticus Gir. 



c 2 Tip and marginal spines of rostrum not bent upward. Fingers of 

 chela gaping to the tips. C. (Faxonius) forceps Fax. 



b 2 Margins of rostrum straight, generally subparallel. Sexual organs reach- 

 ing to the first pereiopods. 

 c x Rostrum with distinct median keel. Sexual organs without shoulder. 



C. ( Faxonius) neglectus Fax. 

 c 2 Rostrum without median keel. Sexual organs with more or less dis- 

 tinct shoulder. 

 d 1 Areola shorter than half of the anterior section of carapace. 



' C. (Faxonius) spinosus Bund. 

 d 2 Areola half as long as the anterior section of carapace. 

 <?j Margins of rostrum almost parallel, 



C. (Faxonius) putnami Fax. 

 e 2 Margins of rostrum distinctly convergent. 



C. (Faxonius) /ty /as Fax. 

 a 2 Rostrum without marginal spines. Carapace without lateral spines. 



C. (Faxonius) medius Fax. 



3. Section of C. virilis (see p. 109). 



1. Group of C. alabanicnsis (seep. no). 

 a x Areola very short. Carapace not compressed. 



C. (Faxonius) alabamensis Fax. 

 a 2 Areola a little longer. Carapace compressed. 



C. (Faxonius) compressus Fax. 



2. Group of C. virilis (see p. no). 



tfj Margins of rostrum concave, acumen moderately long, together with marginal 

 spines bent upward. G. (Faxonius) meeki Fax. 



