324 JOURNAL OF COMPARATIVE NEUROLOGY. 
to the authorities of that institution, for the facilities and schol- 
arship privileges granted me; and to Dr. E. L. Parxs and 
friends, whose cooperation made possible the spending of a 
summer in the above named institution. I am also under lasting 
obligations to Dr. W. M. WuEELER for suggestions and for the 
gift of some Peripatus material and for the loan of an extensive 
collection of insect slides. I must also express my thanks to 
Dr. C. M. Cuitp, who kindly gave me well-fixed specimens of 
several polychete annelids. 
HISTORICAL. 
After the historical accounts given by Emir Yune (’78), 
W. VIGNAL (83), KrizGeR (’88), G. Rerzius (90), JULES 
RICHARD (91), Paut Samassa (91), H. VIALLangs (’93), and 
C. H. Turner (’96), an exhaustive résume of the work already 
done on the crustacean brain would be out of place here. Any 
one interested the subject will do well to consult the works just 
mentioned. The papers of Rerzius (90) and VIALLANES (’93) 
are especially valuable for such a purpose. Throughout the 
text references will be made to the views of the various authors, 
and, at the end of this article, will be found a bibliography .of 
the works on the central nervous system of the Crustacea. In 
this place it is proposed to epitomize the conclusions of only a 
few of the authors who have discussed it. 
Emit Yunc (’78) studied the nervous system of Homarus, 
Palemon, Astacus, Cancer, Portunus, and Maza. A portion of. 
the paper is bibliographical and physiological; in the remainder 
of the paper the author comes to the following morphological 
conclusions: 
1. The brain gives origin to the following seven pairs of 
nerves: the nerve to the frontal organ, the optic nerves, the 
oculomotor nerves, the antennulary nerves, the antennary 
nerves, the tegumentary nerves, and the nerves to the muscles 
of the antennules. 
2. The nervous system of the decapod crustacea has the 
same elementary composition as the vertebrate nervous system; 
i. e., nerve fibers and nerve cells. 
