MEXICAN, CENTRAL AMERICAN, AND CUBAN CAMBARI 19 
not be surprised, if this latter species, of which the male is un- 
known, should finally prove to belong to this group, and not to 
the second group of Faxon (affinity of C. cudenszs) as Hay is in- 
clined to believe. 
The hooks of the ischiopodites of the pereiopods are very pecu- 
liar, and unlike anything else that is known inthe genus. And 
further, the development of the spines and processes of the cox- 
opodites of the three last pairs of pereiopods is very unique ; 
such processes are indeed found in other species in the shape of 
tubercles or ridges on the fourth or fifth pereiopods, but they 
never assume such proportions as in this species, and the out- 
wardly directed spine of the coxopodite of the fourth pereiopod 
in C. weegmannzi is without parallel. 
Thus it seems that C. wzegmannz is to be regarded as a very 
peculiar, and, in certain features, extremely developed form of 
the subgenus Cambarus, which belongs to a rather advanced 
and modern group of it (a//enz-group, see l. c., p. 105) which 
is characteristic for those parts of the coastal plain of the south- 
ern United States, that are most recent geologically. Its pres- 
ence in Mexico is rather interesting, and the specialized char- 
acter points to a recent immigration into these parts. But we 
are to bear in mind that the a//enz-group in general is compara- 
tively poorly known and needs further study. 
VI. Subgenus CAMBARELLUS. 
For the species of this subgenus I am only able to add a few 
new locality records: 
Cambarus (Cambarellus) montezume Saussure (Faxon, 1885, 
£21); (1898,\660). 
Neighborhood of City of Mexico: Laguna de Santa Isabel. 
—G. Seurat coll., 1897 (Mus. Paris, 1 o'(1), 1 ). 
Mexico. — Mus. Paris, numerous specimens, collected by 
various persons, but without more explicit localities. 
Lake Xochimilco, south of City of Mexico (Federal Dis- 
trict). E. D. Cope coll., 1885 (Philadelphia Academy, 1 &). 
Most of the specimens seen by the writer belong to the form 
tridens v. Mart. With Faxon, I do not believe that this is 
worth a varietal name. According to my observations, young 
