THE GH/ETOGNATHA, OR PRIMITIVE MOLLUSCA. 389 



Class 3. Aiupliineura Aplacophora. 



Without shell. 

 „ 4. Amphiiieura Polyplacophora. 



Shells octuple. 

 „ 5. Lamellibranchia. 



Shell bivalve. 

 ,, 6. Gastropoda. 



Shell siugle. 

 ,, 7. Scaphopoda. 



Shell single, tubular. 



MoLLUscAN References. 



GiiAFF, L. VON. — "Anatomic des Clisetodernia nitidulum," ' Zeitschr. 

 wiss. Zool.,' xxvi, 1S75. 



JiiEKiNG, H. YON. — -"Sur les relations naturelles des Coclilides et des Iclino- 



podes," 'Bull, scient. Prance et Belgique,' xxiii, 1891. 

 Keiik, J. GiiAUAM.— " On some Points in tlie Anatomy of Nautilus poni- 



pilius," 'Proc. Zool. Soc.,' 1895. 

 Lankester, E. R. — "Mollusca," 'Encyclopaedia Britannica,' 9th edit., xvi, 



1883. 

 Pelseneer, p. — "Reclierclies morpliologiques et pbylogenetiques sur les 



MoUusques archaiques," 'Mem. Cour. Acad. Belg.,' Ivii, 1899. 



Spillmann, J. — "Herz der Diotocardier," 'Jena Zeitschr.,' xl, J 905. 

 Thiele, J. — "Die Systematisclie Stellung der Solenogastren und diePliylo- 

 genie der Mollusken," ' Zeitschr. wiss. Zool,,' Ixxii, 1902. 



Bibliography of the Ch^tognatha. 



176S, 10 July. — M. Slabber caught a "Zee-worm," which he described in — 

 17G9-78. Slabber, Martinus. — "NatuurkundigeVerlustigungen,behelzende 



microscopise waarueemingeu van In- en Uitlandse Water- en Land- 



Dieren," vi, 3. "Van een Zee-worm genaamd Sagitta of Pyl," 



pi. G, figs. 4, 5. Haarlem. 

 1775. 'Physicalische Belustigungen oder niikroskopische Wahrueh- 



mungeu in- und auslandischer Wasser- und Landthierchen," iiber- 



setzt von Miiller, Niirnberg, pp. 23-4, lig. 

 VOL. 51, PART 3. NEW SERIES. 30 



