GASTEROPODA. 151 



Sub-genus. Hemitoma, Sw. Type, E. octoradiata. (E. rugosa. PI. XL. 

 figs. 7, 8.) Shell depressed ; anterior margin slightly channelled. 



PARMOPHORUS, Blainville. Duek's-bill limpet. 



Etym., parme, a shield, and phoreus, a bearer. 



Type, P. australis. PL XL, fig. 9. Syn., Scutus, Montf. 



Shell lengthened-oblong, depressed ; apex posterior ; front margin arched 

 Muscular impression horse-shoe shaped, elongated. The shell is smooth anc 

 white, and permanently covered by the reflected borders of the mantle. Th< 

 animal is black, and very large compared with the shell ; its sides are fringec 

 with short cirri, and its eyes sessile on the outer bases of thick tentacles ; i 

 is found in shallow- water, and walks freely (Cuming). 



Distr., 10 sp. New Zealand, Australia, Philippines, Singapore, Red Sea 

 Cape. 



Fossil, 3 sp. Eocene ? . Paris basin. 



FAMILY XII. CALYPTILEID^E. Bonnet-limpets. 



Shell limpet-like, with the apex more or less spiral ; interior simple, o 

 divided by a shelly -process, variously shaped, to which the adductor muscle 

 are attached. 



Animal with a distinct head ; muzzle lengthened ; eyes on the externs 

 bases of the tentacles ; branchial plume single. Lingual teeth single, uncini 3 



The bonnet-limpets are found adhering to stones and shells ; most of then 

 appear never to quit the spot on which they first settle, as the margins c 

 their shells become adapted to the surface beneath, whilst some wear awa; 

 the space beneath their foot, and others secrete a shelly base. Both thei 

 form and colour depend on the situation in which they grow ; those found i 

 the cavities of dead shells are nearly flat, or even concave above, and colour 

 less. They are presumed to feed on the sea-weed growing round them, or o: 

 animacules ; a calyptrcea, which Professor Forbes kept in a glass, ate a sma^ 

 sea slug (goniodoris) which was confined with it. Both calyptreea and pile 

 opsis sometimes cover and hatch their spawn in front of their foot (Alder an 

 Clarke). 



Mr. Gray arranges the bonnet-limpets next after the vermetidse ; thei 

 lingual dentition is like velutina. 



CALYPTR^EA, Lam. Cup-and-saucer limpet. 



Etym., catyptra, a (lady's) cap. 



Syn., lithedaphus, Owen. 



Types, C. equestris. PI. XL, fig. 10. C. Dillwynnii, fig. 11. 



Shell conical; limpet-shaped; apex posterior, with a minute, spire 

 nucleus ; margin irregular ; interior with a half-cup shaped process on th 

 posterior side, attached to the apex, and open in front. Surface rugose o 

 cancellated. 



