THE NAUTILUS. 19 



Habitat : unknown, but most probably Bolivian. 



This fine species is quite distinct from others. The nearest ally is 

 E. estella a" Orb., from which it differs in being more globose, im- 

 perforate, in having the peristome more developed with the margins 

 approximate, and many other particulars. It cannot be confounded 

 with E. Tucumanensis Doering, and E. Saltana Anc, from northern 

 Argentina, in which the sculpture is not the same at all and from 

 which the above characters may separate it at a glance. 



NATURAL HISTORY OF THE TRES MARIAS ISLANDS, MEXICO. 



The above is the title of '"North American Fauna, No. 14," re- 

 cently published by the U. S. Dept. Agriculture (Division of Bio- 

 logical Survey). The title should be modified by placing the words 

 " Contributions to the," before the word " Natural," as no mention 

 is made of the Insecta, and only six species of mollusks are given. 

 These are all land shells, and determined by Dr. Dall as follows: 

 Polygyra ventrosala Pfr., Orthalicus undatus Brug., Orthalicus mi- 



datus melanocheilus Val., 1 Lamellaxis ? Opens subula Pfr., and 



Glandina tarn's Pfr. The two forms of Orthalicus were heretofore 

 known to occur in the islands; the others are additions to the list 

 published by the National Museum in 1894. The author of this 

 number of the N. A. Fauna, Mr. E. W. Nelson, in mentioning the 

 names of Col. A. J. Grayson and Alphonse Forrer, says, "no other 

 naturalist is known to have visited the islands until the spring of 

 1897," when in April of that year Mr. Goldman and himself crossed 

 over by sail-boat from San Bias, remaining on the islands from the 

 2d to 31st of May. The summary of animal species collected includ- 

 ing the six mollusks above named sums up 121. The author should 

 have known that the islands were visited in the spring of 1876 by 

 Mr. W. J. Fisher, who made a large collection of molluscan forms 

 as published in the Proc. U. S. National Museum, pp. 139-204, of 

 Vol. XVII, 1894, where 89 species were listed. Four of the land- 



' The Orthalicus of northwestern Mexico is not undatus, which is an exclusively 

 Antillean and Floridian form. It is 0. princeps Brod,, a more boldly marked 

 form than undatus, with distinct ami coarser spiral striation, and various differ- 

 ences in the soft anatomy, which has been worked up by Strebel, and confirmed 

 by my own preparations. Probabiy melanocheilus holds the same relation to prin- 

 ceps that jloridensis does to undatus ; but this has not been proven as yet. — Ed. 



