COLtJMBlAJT UEGIOIT. Ill 



part, and Cistula, part.)* The solitary Clausilia is found in Porto 

 Rico, the Balea in Haiti, and the Tornatdlina in Cuba ; Stenopus 

 is peculiar to St. Vincent's. Bermuda has 4 Helices, of which one 

 is common to Texas and one to Cuba. The Chondropomas are 

 found in Cuba and Haiti. 



The West Indian Achatinm belong to the sub-genera Olandina, 

 Liguus and Spiraxis ; the Bulimi are sharp -lipped and mostly 

 small and slender {SuhuUna, Orthalkus). Helix (Sagda) epis^ 

 tylium, H. CarocoUa^ and Succinea (Amphibulima) patida are 

 characteristic forms. 



Although connected with Florida by the chain of the Bahamas, 

 and with Trinidad by the lesser Antilles, very few species are 

 common to the mainland of either North or South America ; 

 the relation is generic chiefly. 



The Limacidce are represented by Vaginulus (Sloanei) ; and in 

 the fresh waters there are species of Pliysa (3), Flanorbis (8), 

 Ancylus, and the peculiar Oundlachia, Valvata pygmcea, Am- 

 pidlarra (fasciata), Faludeatrina (minute species), Hemisinua, and 

 2 species of Pisidium, 



In the brackish waters are Cerithidium, Neritina {e.g. melea- 

 gris, pupa, virginea, viridis), Melampus (coniformis), and Fedipes 

 quadridens. 



22. Columbian EEGioN.f 



The tract shaded in the map comprehends several minor 

 regions ; 1 , the rainy and wooded states of New Granada and 

 Ecuador ; 2, the elevated and nearly rainless province of Vene- 

 zuela, with a flora like that of the higher regions of the Andes ; 

 3, the Guianas, including the Valley of the Amazon, where the 

 forests are most luxuriant, and rain falls almost daily (amount- 

 ing to 100 or even 200 inches in the year). Most of the low 

 lands, like those of the Mexican Province, belong to the "Cactus 

 Region " of botanists, and have a mean temperature of 68® — 84*'. 

 Land shells are abundant in the forests and underwood of the 

 lower zone of the mountains, where the temperature is 10*^ 

 less and the rains more copious. Bulimi are the predominant 

 forms, especiallythesuccinea-shaped species, (e.g. B. succinoides). 



* A magnificent collection of Jamaica land shells has been presented to the British 

 Museum by the Hon, E. Chittty, whose researches were conducted with the late 

 Professor C. B. Adams. 



t In 1821 the States of New Granada, Venezuela, and Ecuador united to form the 

 " Columbian Republic," but dissolved again in 1831. 



