8 A REVISION OF THE ASTACIDA. 
Vol. I. pp. 402-405. This paper is the same in substance as the last; but C. placidus 
Hage. is omitted from the list, and C. Couwest Streets ? is added. _ 
“1883. The exhibition of living specimens of Cambarus Bartonii from North Grafton, 
Worcester Co., Mass., at the rooms of the Worcester Natural History Society, is recorded 
in “Scientitic 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 
Zovlovy. 
1884. In a note “On the so-called Dimorphism in the Genus Cambarus,” in Amer. 
Journ, Sci., Vol. XX VII. pp. 42-44 (reprinted in Ann. and Mag. of Nat. Hist., 5th Ser. 
Vol. XIIL. 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 deseribes in Nature, Vol. XXX. pp. 127, 128, the burrows of 
C. Diogenes Girard. 
1884. Dr. © 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 Astacidee. The types of all his species 
are in the Museum of Comparative Zodlogy, 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. fallax, Lecontet, versutus, 
luncifer, virilis, placidus, guwenilis, obscurus, immunis, extraneus, and obesus. Of 
these, C. placidus and C. juveniis are in my opinion only forms of the vari- 
‘able species C. rusticus Gir.; C. obscurus, a local variety of C. propinquus Gir. 
C. obesus is the same as C. Diogenes Gir. The remaining species included in 
Hagen’s memoir are C. acutus Gir., Clark Gir., troglodytes (LeC.), Blandingi 
(Harlan), spreulfer (LeC.), angustatus (LeC.), maniculatus (LeC.), penicillatus 
(LeC.), Wiegmannt Erichs., pellucidus (Tellk.), affinis (Say), propinguus Gir., 
rusticus Gir., Bartonii (Fab.), robustus Gir., Nebrascensis Gir., latimanus (LeC.), 
Mexicans Krichs., Cubensis Krichs., advena (LeC.), and Carolinus Erichs. 
C. maniculatus, Nebrascensis, Mexicanus, and Cubensis were known to Hagen 
only through the descriptions of the original authors of the species. C. acu- 
