CAMBARUS. 123 
In Archiv fiir Naturgeschichte, XX XVUI., 1872, page 130, Von Martens 
communicates some remarks upon the form with lateral rostral spines, 
received by the Berlin Museum from Puebla, Mexico, together with the 
typical C. Montezume and C. Aztecus. This form he calls Cumbarus Monte- 
zume, var. tridens. ‘The largest part of those which I have myself seen, 
amounting to about seventy specimens, have the lateral spines on the 
rostrum, but in some specimens the spines are very small, and in others 
reduced to a mere angle at the base of the acumen. 
Some of the female specimens collected by Prof. A. Dugés, in the col- 
lections of the U. S. National Museum, have a short, broad, and hirsute 
chela. 
Five imperfectly preserved dry specimens in the Museum of Comparative 
Zoilogzy come from Mazatlan. These specimens have a rather long, taper- 
ing, entire rostrum, but do not differ from C. Montezuma enough to warrant 
separation. The sexual parts are the same as in the more eastern speci- 
mens. It appears from these specimens that the genus Cambarus extends, 
in Mexico, to the Pacific coast. 
There are also in this Museum six specimens, two males, form I., three 
females, and one young male, collected by Mr. Edward Palmer near Parras, 
Cohahuila, Mexico, which differ from C. Montezume, var. tridens, in having 
the section of the carapace posterior to the cervical groove shorter, the 
areola much broader. This form, which I have named provisionally CO. Mon- 
tezume, var. areolata, may prove to be a good species. But considering the 
variability of individuals of C. Montezume, and the small number of Mexican 
localities from which specimens have been received, I prefer to treat this 
form as a variety simply, the more because the sexual parts of both male 
and female are like those of C. Montezuma. In this form, the distance from 
the cervical groove to the posterior margin of the carapace is half (or even 
less) the distance from the cervical groove to the lateral rostral spines. The 
areola is about half as broad as it is long. Length of body, 28 mm. 
The largest specimen of C. Montezuma which I have seen measures 
38 mm. from tip of rostrum to end of the telson. 
Known Localities. — Mexico: marshes of the Valley of Mexico (Saus- 
sure); ponds, Chapultepec; Lake Tezcoco,* near city of Mexico; Puebla 
(Von Martens); Lake San Roque, Trapuato (Coll. U. 8S. Nat. Mus.) ; Parras ; 
Mazatlan. 
* Lake Tezcoco is said to be salt. 
