FEEDING HABITS OF NEEEIS VIRENS, SARS 439 
nerves of two pairs of tentacular cirri arise from the sub-oesoph- 
ageal ganglion, and those of the others take their origin from the 
circumoesophageal connectives. In the higher animals, the nerves 
of special sense, such as sight, taste, etc., are directly connected 
with the brain. It is reasonable to infer that in a highly organ- 
ized worm like Nereis, we have the beginnings of a concentra- 
tion of sense receptors into more or less limited regions which 
have become secondarily but directly related to a centralized 
brain. This locahzation of the chemical sense has not pro- 
gressed to any great degree, for the whole general integument of 
Nereis, though less sensitive than the palps and tentacles, is 
open to chemical stimulation. The same is true with the light 
sense. The general integument of Nereis is sensitive to light, 
yet there is a tendency toward a localization of the light sense 
in the presence of two pairs of relatively well-developed eyes. 
These eyes are innervated by large nerves which connect directly 
with the brain. The conditions of these sense organs in Nereis 
are intermediate between those forms in which there is only the 
general integumentary sense and the higher forms in which the 
chemical sense is vested solely in special sense organs innervated 
by cranial nerves. 
Maxwell has attempted to show that the feeding responses, 
that is responses due to chemicals or substances given off by 
food, cease when the supra-oesophageal ganglion is removed. 
Maxwell's statement is as foUows: "Operirte Wiirmer beachten 
dagegen angebotenes Futter gar nicht, es sei denn, dass man es 
unsanft auf sie wirft und sie dadurch erschreckt. Sie kriechen 
iiber Stiicke Futters, die in ihrem Wege hegen, als ob es Steine 
oder anderes lebloses Material ware. Obschon ich diese Wiirmer 
viele Wochen hindurch gehabt habe, ist es mir nicht in einem 
einzigen Falle gelungen, sie zu fiittern. Mit dem Verlust des 
supraosophageschen Ganglions scheint das Thier die Fahigkeit 
verloren zu haben die spezifischen Reaktionen auf die chemischen 
Reize, die vom Futter ausgehen, zu zeigen." 
Maxwell's experiments show that the removal of the supra- 
oesophageal ganglion changes the responsiveness of the worms to 
chemical stimulation — a result which is in direct line with what 
