12 A REVISION OF THE ASTACIDA. 
Types of six of Le Conte’s species (described in 1855) are preserved in 
the Academy of Natural Sciences of Philadelphia : A. troglodytes, A. spiculifer, 
A. fossarum, A. angustatis. A. latimanus, and A. advena. The Museum of Com- 
parative Zoilogy also possesses types of A. troglodytes, A. smeulifer, A. fossa- 
rum, A. latimanus, and A. advena. A. fossarwin is not separable from A. trog/o- 
dytes. Le Conte’s A. maniculatus remains yet unknown. (See p. 29.) 
The Two Forms of the Males.—In every species of Cambarus, of which 
many specimens have been examined, two forms of the adult male have 
been found, characterized by striking differences in the conformation of the 
sexual parts. In the form called the first by Dr. Hagen, the external organs 
peculiar to the male are more perfectly formed than in the “second form,” 
where they have somewhat the shape seen in the young male. The pecu- 
liarities of each of these forms have been fully described by Hagen,* to 
whose monograph the reader is referred for details. No intermediate con- 
ditions between these two forms exist, and there is no fixed relation between 
them and the size of the individual, males of the second form being often 
larger than those of the first, or vice versa. They cannot, then, be consid- 
ered developmental stages. Dr. Hagen interpreted the facts as a case of 
dimorphism, and surmised that the second form males were sterile indi- 
viduals ; but I have since shown that males of the first form after the breed- 
ing season may revert to the second form by moulting.| The two forms 
of the male Cambarus, instead of being dimorphic forms, are probably alter- 
nating conditions in the life of one individual, the first form bemg assumed 
during the pairing season, the second form during the interval between 
the pairing seasons. The second form is probably impotent; the testes are 
smaller than in the first form, the vasa deferentia shorter,t but I have had 
no opportunity as yet to examine their microscopic structure. 
Tuications of Hermaphroditism in Cambarus.— Perhaps the only recorded 
ease of undoubted hermaphroditism in the Decapod Crustacea is that of the 
lobster (Homarus vulgaris) described and figured by F. Nicholls in 1750.§ In 
* Pages 21, 292. 
+ On the So-called Dimorphism in the Genus Cambarus, by Walter Faxon. Amer. Jour. Sci., Vol. 
XXVII. pp. 42-44, January, 1884. 
* See Hagen’s Plate IT. 
§ An Account of the Hermaphroditic Lobster presented to the Royal Society by Mx. Fisher, examined 
and dissected, by I. Nicholls. Philosoph. Trans. Roy. Soc. London, Vol. XXXVI. No. 413, p. 290, 1730 
(Abridgment, Vol. VII. Pt. TIT. p. 421, Pl. IV., 1734). For a general account of hermaphroditic and other 
anomalous conditions among the Crustacea, see Faxon, On Some Crustacean Deformities, Bull. Mus. Comp. 
Zool., Vol. VIII. No. 13, 1881. 
