GASTEROPODA. 105 



ritius, China, New Zealand, Pacific, West America. On reefs, at low water, 

 and ranging to 1 fathoms. 



Fossil, 5 cretaceous species ; 3 sp. Miocene . South Europe. There is a 

 group of small shells in the eocene tertiary strata of England and France, 

 nearly related to the living S. fissurellus L., some of which have been placed 

 with rostettaria, because the notch in the outer lip is small, or obsolete. They 

 probably constitute a sub -genus, to which Swainson's name strombidia, might 

 be applied. Example, S. Bartonensis. PL IV., fig. 2. 



The fountain-shell of the West Indies, S. gigas, L., is one of the largest 

 living shells, weighing sometimes four or five pounds ; its apex and spines are 

 filled up with solid shell as it becomes old. Immense quantities are annually 

 imported from the Bahamas for the manufacture of cameos, and for the 

 porcelain works ; 300,000 were brought to Liverpool alone in the last year, 

 1850 (Mr. Archer). 



PTEROCERAS, Lam. Scorpion-shell. 



Etym., pteron, a wing, and ceras, a horn. 



Type, P. lambis. PL IV., fig. 3. 



Shell like strombus when young ; outer lip, of the adult, produced into 

 several long claws, one. of them close to the spire, and forming a posterior 

 canal. 



Distr., 10 sp. India, China. 



Fossil, nearly 100 sp. are enumerated by D'Orbigny, ranging from the 

 lias to the upper chalk ; many of them are more nearly related to aporrhais 

 (certthiadue). 



ROSTELLARIA, Lam. 



Etym., rostellum, a little beak. 



Syn., fusus, Humphreys. 



Example, R. curta. PL IV., fig. 4. 



Shell with an elongated spire ; whirls numerous, flat ; canals long, the 

 posterior one running up the spire ; outer lip more or less expanded, with 

 only one sinus, and that close to the beak. 



Distr., 5 sp. Red Sea, India, Borneo, China. Range, 30 fathoms. 



Fossil, 70 sp. Neocomian chalk (=aporrhais ?). 6 sp. Eocene . 

 Britain, France, &c. 



The older tertiary species have the outer lip enormously expanded, and 

 smooth-edged ; they constitute the section hippochrenes of Montfort (e. g. 

 Rost. ampla, Solander. London clay). 



Sub-genus;" Spinigera, D'Orb. 184?. Shell like rostellaria ; whirls 

 keeled ; keel developed into a slender spine on the outer lip, and two on each 

 whirl, forming lateral fringes, as in ranella. Fossil, 5 sp. Inf. oolite- 

 chalk. Britain, France. 



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