68 ASTACID^. 



apicem versus latiori, margine externo sinuato, modice inflato, aj^ice 

 spina longiori. Epistomate antice angustiori, truncato, climidio latiori, 

 lateribus excisis. Pedibus maxillaribus externis intus parum villosis, sub- 

 tus nudis. Thorace subovoideo, parum-punctato, laterilms subtilissime 

 granulosis ; liuea j^rofunda, subsinuata, lateribus divisa, spina laterali 

 acuta; areola plana, paulo latiori, antice posticeque a^quo dilatata. 

 Postabdomine thorace subangustiori, fere liBvi, segmentis penultimis 

 angulo externo mutico ; lamina media parte apicali breviori, subangus- 

 tiori, rotundata ; parte basali quadrangulari, antice utrinque bispinosa. 

 Pedibus anticis brevibus, chela modice lata, suljdepressa, punctata, sub- 

 tus la3vi, margine interno brevi, recto, paululum serrato ; digitis fere 

 duplo longioribus, rectis, margine interno costato-lineatis, basi intus 

 subdentatis. Carpo lato, oblique truncato, sublajvi, spina media in- 

 terna, subtus spina solum externa antica valida. Brachio brevi, Vxv'i, 

 spinis duabus anteapicalibus oblique positis, spinis inferis biseriatis, dua- 

 bus anticis exceptis subnullis. Pedibus tertiis articulo tertio unguicu- 

 lato. Pedibus quintis capitulo basali cjlindrico. Pedibus alxlominali- 

 bus brevioribus, subcontortis, apice modo bifidis, partibus cylindricis, 

 crassioribus, a^qualibus, parte interna, apice subacuta paulo introrsus 

 curvata, parte externa fusco-cornea, tenuiori, acuta. 



Forma 11. differt chela angustiori, crassiori, la?viori ; pedibus abdonii- 

 naliljus, basi articulatis (interdum non articulatis) partibus apicalibus 

 ajqualibus, parte externa non fusco cornea. 



Femina diftert chelis minoribus; ventre inter pedes quartos ItBvi, 

 annulo oljovato, subdepresso, fissura longitudinali dentata, apertura 

 transversali nulla. 



Long. corp. 2.6 ; long. ped. ant. 2.3. 



Ordinarily, long. corp. 1.5 at 2. 



Patria: Lake Oneida; Lake Superior; Niagara; Ogle County, Illi- 

 nois ; Delphi, Lidiana ; Rochester, N. Y. 



I have seen many examples. In one abnormal male the third pair 

 of legs are not hooked ; some males have the third joint of the second 

 pair of legs hooked. 



A male type (Forma I.) found by Professor Baird on Grass River, St. 

 Lawrence County, N. Y., and communicated by Professor Stimpson, is 

 identical with the specimens from Lake Superior. Mr. Girard has seen 

 specimens of this species from Lake Ontario, Garrison Creek, Sackett's 

 Ilarljor, Four-Mile Creek, Oswego. 



In one abnormal male the first pair of the abdominal legs are not 

 developed, but they have the same shape as those of the females. 



One male, Delphi, Indiana, is larger, long. corp. 3.2 ; ped. ant. 3.1, 

 but very similar. The hands are more developed, as is commonly the 

 case in old males ; the abdominal legs are similar in form, but the pos- 

 terior margin is a little hooked in the middle, and more emarginated 



