'2 MOLLUSCA. 



350 fathoms. The pelagic forms are not only distributed over the 

 surface of the sea, but may descend to a depth of 2,600 fathoms with- 

 out reaching the bottom. Abyssal molluscs are found in all oceans, 

 extending to a depth of 2,800 fathoms from the .surface. 



The different classes of molluscs were already differentiated at a 

 remote epoch of the Palaeozoic era. 



LITERATURE OF THE MOLLUSCA GENERALLY. 



I. Concholpgical. 



Adams, H. and A. " The Genera of Recent Mollusca." 1853-58. 



Cooke. " Molluscs." " The Cambridge Natural History," vol. iii. 1895. 



Fischer. " Manuel de Conchyliologie." 1887. 



Forbes and Hanley. " British Mollusca." 1853. 



Jeffreys. " British Conchology." 1862-69. 



Martini and Chemnitz. " Systematisches Conchylien Cabinet." 



Simroth. '' Mollusca." ' Bronn's Klassen und Ordnungen des Tier- 



reichs," vol. iii, from 1895. 

 Taylor. :< Monograph of the Land and Fresh-water 'Mollusca of the 



British Isles," from 1900. 



Tryon-Pilsbry. " Manual of Conchology," from 1878. 

 Woodward. " A Manual of the Mollusca." 1880. 



II. Morphological. 



Cuenot. " L'Excretion chez les Mollusques." Arch, de Biol., xvi, 1899. 

 Geddes. " On the Mechanism of the Odontophore in certain Mol- 

 lusca." Trans. Zool. Soc. London, x, 1879. 

 Huxley. " On the Morphology of the Cephalous Mollusca." Phil. 



Trans., 1853. 



von Ihering. " Vergleichende Anatomic des Nervensystems und Phy- 

 logenie der Mollusken." 1877. 



' Die Gehorwerkzenge der Mollusken." 1876. 

 " Zur Morphologic der Niere der Mollusken." Zeitschr. 

 f. wiss. Zool., xxix, 1877. 

 Lankester. ' Mollusca." Encyclop. Brit., ed. 9 ; xvi, 1883. 



" Contributions to the Developmental History of the Mol- 

 lusca." Phil. Trans., 1875. 



" Note on the Ccelom and Vascular Svstem of Mollusca 



and Arthropoda." Quart. Journ. Micr. Sci., xxxiv, 1893. 



Milne-Edwards. ''' Observations sur la Circulation chez les Mol- 

 lusques." Ann. d. Sci. Nat. Zool., ser. 3, viii, 1847. 



Moynier de Villepoix. ' Recheches sur la Formation et 1'Accroisse- 

 ment de la Coquille." 



Pelseneer. " Introduction a 1' Etude des Mollusques." 1894. 



- "Mollusca." Ray Lankester: "A Treatise on Zoology," 

 part v, 1906. 



Lang. '' Lehbruch der vergleichenden Anatomic der wirbellosen Tiere," 

 iii, 1900 : Mollusca von K. Hescheler. 



