8 A KEVISION OF THE ASTACID.E. 



Vol. I. pp. 402-405. This paper is the same in substance as the last ; but C. placid us 

 Hag. is omitted from the list, and C. Couesi Streets ? is added. 



1883. The exhibition of living specimens of Centibar us Burtonii from North Graftou, 

 Worcester Co., Muss., at the rooms of the Worcester Natural History Society, is recorded 

 in " Scientific and Literary Gossip," Vol. I. p. 113. The only locality in this State 

 hitherto known was Williamstown, in Berkshire Co. Through the kindness of Mr. F. G. 

 Sanborn these specimens are now in the collection of the Museum of Comparative 

 Zoology. 



1884. In a note " On the so-called Dimorphism in the Genus Cambarus," in Amer. 

 Journ. Sci., Vol. XXVII. pp. 42-44 (reprinted in Ann. and Mag. of Nat. Hist., 5th Ser. 

 Vol. XIII. pp. 147, 148), I suggested that the two forms of the male Cambarus were 

 alternating conditions of the same individual connected with the reproductive seasons, 

 and not dimorphic forms, as was commonly supposed. (See p. 12.) 



1884. Mr. Ralph S. Tarr describes in Nature, Vol. XXX. pp. 127, 128, the burrows of 

 C. DiiHjnu'x Girard. 



1884. Dr. C C. Abbott, in the American Naturalist, Vol. XVIII. pp. 1157, 1158, 

 takes exception to Mr. Tarr's conclusion that the mud chimneys built by C. Diogenes are 

 the accidental result of the excavation of the burrows. 



1884. Descriptions of the new species of Cambarus found during the preparation of 

 this Revision, together with a synonymical list of the species of Cambarus and Astacus, 

 were published by me in the Proceedings of the American Academy of Arts and Sciences, 

 Vol. XX. pp. 107-158, December, 1884. 



Dr. Hagen's Monograph must ever remain the foundation for all sys- 

 tematic work on the North American Astacidoe. The types of all his species 

 are in the Museum of Comparative Zoology, and have been constantly 

 before me in the preparation of the present Revision. With far ampler 

 material at my disposal than fell to Dr. Hagen's lot, I have seldom had 

 occasion to differ from him in his conclusions concerning the species known 

 to him. Thirty-two species of Cambarus are described by Dr. Hagen. Of 

 these, eleven are described as new species ; viz. C. fttllt/.r, Lecontei, versittus, 

 lititcifcr, viriiis, pladdus, juvcnilis, obscunts, immunis, extntncns, and obcsus. Of 

 these, C. plactdus and C. juvcnilis are in my opinion only forms of the vari- 

 able species C. rusticus Gir. ; C. olscitms, a local variety of C. propinqmis Gir. 

 C, obesus is the same as C. Diogenes Gir. The remaining species included in 

 Hagen's memoir are C. acutiis Gir., ClarJdi Gir., troglodytes (LeC.), Blandhu/ii 

 (Ilarlan), sjncitllfcr (LeC.), angustatus (LeC.), mauicitlatus (LeC.), pcnicittattis 

 (LeC.), WifgriKinni Erichs., pcllticidus (Tellk.), affinis (Say), propinqmis Gir., 

 ruslieus Gir., Bartonii (Fab.), rolustus Gir., Nclrasccnsis Gir., latiinioitis (LeC.), 

 jr,:r/ranns Erichs., Cubcnsls Erichs., advcna (LeC.), and Carolinus Erichs. 

 C. iiKi.ni<-<illns, Ncbrascensis, Mcxlcamis, and CW*W. were known to Hagen 

 only through the descriptions of the original authors of the species. C. acn- 



