No. 26.] ARTHROSTRACA OF CONNECTICUT. IQI 



CYMOTHOIDEA or FLABELLIFERA. ASELLOIDEA Of ASELLOTA. 



Anthuridae. Asellidae. 



Cyathura carinata (Kroyer). ^Asellus communis Say. 

 Ptilanthura tennis Harger. Janiridae. 



Cirolanidae. ftzra marina (Fabricius). 

 Cirolana concharum (Stimpson). BOPYROIDEA or EPICARIDEA. 



yEgidae. Bopyridse. 



JEga psora (Linn). *Stegophryxus hyptius Thompson. 



Cymothoidse. *Probopyrus pandalicola (Packard). 

 JEgathoa oculata (Say). ONISCOIDEA. 



Livoneca ovalis (Say). Oniscidae. 



Limnoriidae. $Oniscus asellus Linn. 



Limnoria lignorum (Rathke). Philoscia vittata Say. 



Sphseromidse. \Cylisticus convexus (DeGeer). 



Sphceroma quadridentatum Say. %Porcellio rathkei Brandt. 



IDOTHEOIDEA or VALViFERA. $P. spinicomis Say. 



Idotheidae. 



scaber Latreille. 



Chiridotea cceca (Say). $Metoponorthus pruinosus (Brandt). 



C. tuftsii (Stimpson). Actoniscus ellipticus Harger. 



*Idothea metallica Bosc. Armadillididas. 



/. baltica (Pallas). $Armadillidium vulgar e (Latreille). 



/. phosphorea Harger. Scyphacidae. 



*Scyphacella arenicola Smith. 



KEY TO THE GENERA OF ISOPODA. 

 A. First pair of legs chelate, uropods terminal. 



B. Uropods simple, short, uniramous, pleopods three pairs 



Tanais p. 193 

 BB. Uropods biramous, pleopods five pairs ..... Leptochelia p. 195 



AA. First pair of legs not chelate. 

 B. Uropods lateral. 



C. Outer ramus of uropods arching over base of telson. 



D. Maxillipeds with uniarticulate palp ...... Ptilanthura p. 200 



DD. Maxillipeds with biarticulate palp ........ Cyathura p. 198 



CC. Outer ramus of uropods not arching over base of tel- 



son, and uropods not inflexed ventrally. 

 D. Abdomen of six segments. 



E. Uropods with one ramus rudimentary ...Limnoria p. 211 

 EE. Uropods with both rami well developed. 



F. Maxillipeds with palp free and margins of last two 



joints never furnished with hooks ...Cirolana p. 203 

 FF. Maxillipeds with palp embracing distal portion of 



buccal mass. 

 G. Both pairs of antennae with peduncle and flagellum 



well defined .......................... .SSga p. 205 



GG. Antennae much reduced, without clear distinction 



between peduncle and flagellum. 

 H. Head produced posteriorly in three lobes, a 

 larger median one and two small lateral 

 ones ........................... .ffigathoa p. 207 



HH. Head not produced posteriorly. .Livoneca p. 209 

 DD. Abdomen of two segments ............. Sphaeroma p. 212 



CCC. Uropods inflexed ventrally and valve-like. 



