60 ASTACID^E. 



15. Cambarus affinis Say. 



Astacus affinis Say, Journ. Fhilad. Acad., T. 1, p. 1G8, n. 3. — Harlan., Med. Physic. Researches, 



p. 230, fig. 2. 

 Figures on PI. I., III., and V. 



First abdominal legs of the male (full-grown C. Pealei) : 



first form, fig. 84 in front, fig. 85 outside. 

 Common size : 



first form, fig. 1!) in front, fig. 20 outside. 



second form, fig. 21 in front, fig. 22 outside. 

 Antennal lamina, fig. 152, a; epistoma, h ; spine of the second joint of the exterior antenna, c. 

 PI. V. Full-grown female (C Pealei) from Maryland, Havre de Grace. 



Mas. Corpore pubescente ; rostro lato, parallelo, basi media late ex- 

 cavata, utrinque ad marginem linea impressa, ciliata; aeumine angusto, 

 triangulari, acuto, parti dilatatae fere sequali, marginato, apice subre- 

 eurvo, basi utrinque spina acuta longiori ; cretis validis, extus sulcatis, 

 parallelis, spina apicali longiori. Antennis validis thoracis longitudine ; 

 articulis duobus basalibus dente externo acuto longiori ; antennis in- 

 tends articulo basali dente infero medio acuto longiori ; lamina longa, 

 rostri longitudine, lata ad apicem attenuata, margine externo late in- 

 flato, spina apicali valida. Epistomate lato eliptico, basi angustiori. 

 Pedibus maxillaribus externis intus, basi subtus villosis. Thorace ovoi- 

 deo, punctato-pubescente, lateribus leviter, antice magis granulosis ; 

 cepbalothoracis lateribus spinis nonnulis minoribus; linea profunda, vix 

 sinuata, utrinque fissa, spina acuta, valida ; spina apicali, infera, acuta ; 

 areola modica, plana, antice posticeque a?que latiori. Postabdomine 

 thorace longiori, lato, fere la3vi, segmentis jienultimis angulis externis 

 subrectis ; lamina media parte apicali breviori rotundata ; parte basali 

 utrinque apice bispina ; lamina laterali usque ad marginem costata; 

 lamina externa toto margine intermedio dentato. Pedibus anticis bre- 

 vibus, chela brevi, angusta, depressa, punctato-ciliata, margine interne 

 subrecto, serrato, margine externo lineato ; digitis paulo longioribus, 

 rectis, subcostatis, margine interno recto, spongioso ; chela subtus parce 

 punctata, digitis magis ciliatis. Carpo longo, oblique truncato, jmnc- 

 tato-ciliato, spina media aliaque antica minori, intends acutis; subtus 

 spinis duabus acutis validis. Brachio brevi, lasvi, spinis duabus ante- 

 apicalibus acutis validis, oblique positis ; subtus spinis nonnullis validis, 

 acutis, biseriatis. Pedibus tertiis articulo tertio articulato; pedibus quin- 

 (is capitulo basali annulari. Pedibus abdominalibus, brevibus, validis, 

 rectis, subcontortis, apice breviter bifidis ; parte interna cylindrica, 

 apice cornea, laminata ; parte externa a?quali, apice recurva, cornea, 

 acuta. 



Forma II. differt pedibus abdominalibus basi articulatis. apicibus nee 

 fuse) corneis, parte interna conica, acutiori, externa obtusion recurva. 



Femina differt ventre inter pedes quartos la3vi ; annulo obovato, 



