86 ZOOLOGY. 
nacre very brilliant and iridescent. As the animal increases in size a new © 
hole is formed in the shell, and the oldest one is closed. The head is 
proboscidiform, with two long tentacles, each with an oculiferous peduncle ; 
foot large, provided above with a double membrane scolloped into leaflets ofa 
very ornamental character.. The water is admitted to the branchie through 
the holes in the shell, which also allow certain filamentous appendages of the 
mantle to protrude through them. There are two pectinated branchize. The 
genus Stomatia is allied to Haliotis, but the shell has no perforations. This 
sub-family was included by Cuvier among the Aspidobranchia, but Deshayes 
assigns good reasons for placing it among the Ctenobranchia. | 
Neritina (NV. fluviatilis, pl. 75, jig. 87) is a genus of small sub-globular 
or oval fluviatile shells, with a semi-circular aperture closed by a calcareous 
operculum. The two tentacles are long, and each is accompanied by a 
short secondary tentacle, with an eye upon its summit. 
Fam. 5. Pyramidellide. This is a small family, composed of the genera 
Pyramedella and Tornatella. 
Fam. 6. Buecinide. In Buccinum (B. undatum, pl. 75, fig. 120), the 
foot is narrow, the head small, continued in a proboscis, with two tentacles, 
each having an exterior oculiferous peduncle; siphon protruding; sexes 
distinct, the male with a long exterior organ from the right side of the neck ; 
shell oblong-oval, with a notch anteriorly. The species figured inhabits both 
sides of the North Atlantic. The genus has numerous species, both recent 
and fossil. Nassa and Eburna belong to this family. Hdurna glabrata is 
an Ancillaria, and Deshayes thinks the remaining species of Eburna should 
be merged into Buccinum. 
Fam... Purpuride. This marine family is mostly carnivorous; the 
water is taken to the branchie through a siphon, which passes out of the 
notch or canal at the anterior part of the shell. The eyes and tentacles are 
two in number, and the proboscis is well developed. The operculum is thin, 
and much smaller than the aperture, to allow the animal to withdraw some 
distance within the shell. Cancellaria is placed in this family, although it has 
no operculum, and lives upon vegetable food. The animal resembles Purpura. 
Purpura lapillus (pl. 75, jig. 118) is about an inch long, and abundant 
on rocky coasts on both sides of the Atlantic. 
Pleurotoma (P. babylonia, pl. 75, jig. 110) is a genus with an elongated 
spire, a straight canal, and a narrow notch posteriorly in the right lip of the 
shell, corresponding to a notch in the mantle. The species of this genus 
are numerous, amounting to over a hundred of recent, and more than this 
number of fossil tertiary species. There have been nearly fifty species 
described from the tertiary formations of the United States. 
Murex (M. ramosa, pl. 75, fig. 111; M. haustellum, fig. 112; WM. 
tribulus, fig. 113). Rondeletius and Aldrovandi have treated of this 
and some allied genera. The genus murex of Linneeus was founded in 
1758, but Rondeletius had named several of the species purpura, under 
the belief of their being the purpure of Pliny, which were supposed to 
furnish the purple of the Tyrians. The shell named Murex by Pliny and 
Rondeletius, belongs to the medern genus Strombus. Murex is a genus of 
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