856 PROCEEDINGS OF THE NATIONAL MUSEUM. vouxxi. 



IV. ASELLOTA. 



ANALYTICAL KEY TO THE FAMILIES OF ASELLOTA.' 



a. Lateral parts of cepbalon scarcely expanded. Eyes, when present, small, late- 

 eral. Peduncle of inferior antenna? without small accessory appendage outside 

 of third joint. Legs ambulatory, except first pair, which are distinctly sub- 

 cheliform; legs with dactylus generally uniunguiculate. First pair of pleo- 

 poda in female very small, not operculiform. Outer lamella of second pair 

 very large and incrusted, so as to form, together with corresponding lamella? of 

 other side, a sort of operculum, covering the two succeeding pairs. 



Family XI. Asellidte (p. 856). 



a'. Lateral parts of cephalon usually lamellarly expanded. Eyes, when present, 

 usually subdorsal. Peduncle of inferior antennie generally with small acces- 

 sory appendage outside of third joint. Legs subequal in length with dactylus 

 generally bi- or triunguiculate; first pair sometimes prehensile. First pair of 

 pleopoda in female transformed into a single, large opercular plate. Outer 

 lamelhe of two succeeding pairs narrow and confiuent with basal part. 



Family XII. Janirid/E (p. 856). 



Family XI. ASELLID^. 



24. ASELLUS Geoffrey. 



Dactyli of last six pairs of periopoda uniungaiculate. Lateral mar- 

 gins of segments produced. Eyes distinct, lateral. Mandibles strong, 

 with a three-jointed palp. Head without rostrum. 



66. ASELLUS TOMALENSIS Harford. 

 Asellus tomalensis Harford. Proc. Cal. Acad. Sci., VII, 1877, Pt. 1, pp. 54, 55. 

 Habitat. — Tomales Bay, California. 



Family XII. JANIRID^. 



analytical key to the genera of janikid^. 



a'.* Eyes dorsal. AntenuEe of first pair well developed, with multiarticulate flagel- 

 lum. Anteuuic of second pair long, with multiarticulate flagellum, pedun- 

 cular joints not dilated. Mandibles with a three-jointed palp, and with 

 cutting part separated from molar part by a deep incision. 



i. Head without any true rostrum. First pair of antennjo extremely small with 

 llagellum rudimentary. Second pair of antenn.c of moderate length, with- 

 out any distinctly squaraiform appendage. First pair of legs not prehen- 

 sile. Uropoda extremely small, branches very short, nodiform.. 25. Jccra. 



v. Head with prominent rostral projection, or with a comparatively small rostrum, 

 or without rostrum. First pair of antenniB well developed ; flagellum multi- 

 articulate. Second pair of antennte very much elongated with a well- 

 marked scalelike appendage outside of third joint. First pair of legs pre- 

 hensile, carpus large, subfusiform, and edged inside with spines; propodus 

 narrow, linear, and very movably articulated to carpus, so as to admit of 

 being bent in against it. Uropoda largely developed, with branches 

 slightly unequal. 



> Sars, Crust, of Norway, II, 1897, Pts. 5, 6, pp. 95, 98. 

 sidem, Pts. 5, 6, pp. 98-100, 103,104. 



