152 MOLLUSC A 



the esophagus, and being intimately connected with the 

 pleural ganglia, each cerebral ganglion is connected with the 

 corresponding buccal and pedal ganglion and, through the 

 pleural, with the parietal ganglion. The parietal ganglia are 

 connected with each other by a long commissure on which the 

 visceral ganglion is placed. Each pedal ganglion receives con- 

 nectives from the cerebral and from the pleural ganglion of 

 the corresponding side. 



Draw figures of the nervous system and compare them 

 with the clay model. 1 



The dissections of the circulatory and digestive systems 

 may now be completed. 



Colton: How Fulgur and Sycotypus Eat Oysters, Mussels, and Clams. 



Proc. Acad. Nat. Sci., Philadelphia, 1908. 

 Conklin: The Embryology of Fulgur: A Study of the Influence of 



Yolk on Development. Proc. Acad. Nat. Sci., Philadelphia, 1907. 



: The Embryology of Crepidula. Jour. Morph., 13, 1897. 



Copeland: The Olfactory Reactions and Organs of the Marine Snails, 



Alectrion obsoleta and Busycon canaliculatum. Jour. Exp. Zool., 25, 



1918. 

 : Locomotion in Two Species of the Gastropod Genus Alectrion 



with Observations on the Behavior of Pedal Cilia. Biol. Bull., 37, 



1919. 

 Crozier: On the Use of the Foot in Some Mollusks. Jour. Exp. Zool., 



27, 1919. 

 Dakin: Buccinum. Liverpool Marine Biol. Com. Memoir No. 20, 1912. 

 Glaser: tiber den Kannibalismus bei Fasciolaria tulipa (var distans) 



und deren larvale Excretionsorgane. Zeit. f. wiss. Zool., 80, 1905. 

 Herrick: Mechanism of the Odontophoral Apparatus in Sycotypus 



canaliculars. Am. Nat., 40, 1906. 

 Olmstead: Notes on the Locomotion of Certain Bermudian Mollusks. 



Jour. Exp. Zool., 24, 1917. 

 Orton: An Account of the Natural History of the Slipper-Limpet 



(Crepidula fornicata). Jour. Marine Biol. Assoc, 9, 1912. 

 Parker: The Mechanism of Locomotion in Gastropods. Jour. Morph., 



22, 1911. 

 Patten: The Embryology of Patella. Arb. Zool. Inst. Wien, 6, 1886. 



1 Instructors will find that a model prepared by sticking lumps and 

 strands of modeling clay on a cylindrical graduate to illustrate the posi- 

 tions of the ganglia and connectives on the esophagus will greatly aid 

 the students. 



