author's abstract of this paper issued 

 bt the bibliographic service, october 13. 



THE CENTRAL NERVOUS SYSTEM OF SIMPLE 

 CRUSTACEA 



WILLIAM A. HILTON 



Department of Zoology, Pomona College, Claremont, California 



THIRTEEN FIGURES 



Although the general form of the nervous system of branchio- 

 pod Crustacea is well known, there has been very little recent 

 work. Most papers deal with the general form and arrangement 

 of the ganglia and not at all with the structure and arrangement 

 of cells. Zaddach, '41, wrote on Apus. Leydig, '51 and '60, 

 considered Artemia. In 1853 there is the paper of Grube on 

 Limnetis. The work of Claus on Branchipus, Daphnea, Estheria 

 and Apus appeared in 1873, 1876, and 1876, and that of Weis- 

 mann on Leptodora in 1874. Spangenberg's publication on 

 Limnadia was in 1878. Packard has something of the general 

 anatomy of Estheria and Branchipus in 1883. The well known 

 and often copied work of Lancaster on Apus, *81, was followed 

 by that of Pelseneer on the nervous system of the same genus in 

 1884. Spencer in 1902 discusses and figures the anterior nerves 

 of the brains of Artemia and Branchipus. 



From the various observations the general ladder-like type of 

 nervous system has been described and figured in this group of 

 Crustacea. There is the supraesophageal ganglion with its 

 marked region of optic nerves, while the two other pairs of nerves 

 to the antennae and antennules are less marked and come from 

 more caudal portions of the brain or on or near the esophageal 

 connectives. From the cephalic margin of the brain are the 

 median eye branch and the two small pairs of nerves lateral to 

 it, at least in Branchipus and Artemia, as described by Spencer, 

 '02. Each segment of the body below the brain is ordinarily 

 represented by a pair of ganglia connected across the middle hne 



429 



