22 
SHELL GALLERY. 
Case 94. 
distinct kinds are known, is a great favourite with collectors on account 
of the brilliant colours and various patterns of the shells. Some, owing 
to their beauty and rarity, have been sold at very high prices, as 
much as £50 having been paid for a single shell. The Cones are 
found in all tropical seas, but are rare in cold or temperate latitudes. 
None are met with on our own shores, one species alone being known 
from the Mediterranean. They occur fossil in the Chalk and Ter- 
tiary strata. These animals are all carnivorous, and live usually in 
shallow water among rocks and coral-reefs. Some of them are said 
to bite when handled, and to be dangerously poisonous, the bite in 
some instances having been all but fatal. 
The Atlantida, Pterotracheidce, and Carinariidce, at various times 
recognized as forming a distinct sub-class or order of Gastropoda, 
Fisr. 15. 
Glassy Nautilus (Carinaria lamarclti). 
a, proboscis ; b, tentacles ; c, shell ; d, gills ; e, foot ; /, sucker. 
under the name of Heteropoda or Nucleobranchiata, are now regarded 
as families of aberrant Gastropods organised for swimming in the 
open sea. The Atlanfas are found in great numbers in warm lati- 
tudes, and are provided with a glassy, thin, flat, spiral shell, not 
unlike a keeled Ammonite. The glassy shell of the Carinaria is one 
of the most beautiful structures of any mollusc, and at one time was 
such a rarity that £100 are said to have been given for a single 
specimen, which at the present time is perhaps worth only from five 
to ten pounds. Species of Carinaria are found in the Mediterranean 
and warmer parts of the Atlantic and Indian Oceans. The animal 
is large, semitransparent, and elongate, with a compressed fin-like 
foot which projects from the body, and is used in swimming. The 
gills are placed towards the hinder part of the back and covered by 
the shell. They feed on jelly-fish of various kinds, and probably on 
other soft animals. 
