FAMILY 1. MELANIANA. 119 
phonal appendage, but the organ in either form is only found in such as 
are carnivorous. 
The great series of Pectinibranchiate Gasteropoda may first be advan- 
tageously divided into two grand sections according to the nature of their 
feeding ; some being zoophagous, carnivorous or living upon flesh, others 
phytiphagous, or living upon vegetable food: it is an arrangement pro- 
posed by Cuvier, and adopted by most succeeding naturalists. They are 
all protected with solid, well-developed shells, but the zoophagous divi- 
sion exhibits by far the greater variety of form, colour and external de- 
velopment: it is only this portion of the series, too, that is provided with 
a siphon: they are, moreover, armed with a strong retractile proboscis, 
for the purpose of destroying their prey. 
Twelve distinct families may then be referred to this order, dividing 
the flesh-eating kinds from the plant-eating kinds, as follows : 
PHYTOPHAGA: ZOOPHAGA: 
MELANIANA. PARASITICA. 
PERISTOMATA. CANALIFERA. 
NERITACEA. ALATA. 
JTANTHINEA. PuRPURIFERA. 
PLICACEA. CoLUMELLATA. 
TURBINACEA. ConvoLutTa. 
Family 1. MELANIANA. 
Testa turriculata, columella interdum superné incrassata, apertura vel 
integra, vel emarginaté, marginibus disjunctis. Animal fluviatile, 
operculo corneo instructum. 
The Melaniana have little affinity with the preceding family, so far as 
regards their system of organization, but nevertheless agree in their par- 
ticular habit of being confined to fresh water: they differ essentially from 
