JOURNAL OF ENTOMOLOGY AND ZOOLOGY 141 
valve lined with cubical cells, bearing remarkably long and 
heavy cilia. The external opening of the kidney is by a short 
slender canal that ends on the anal papilla, just in front of 
the anus. 
Tue Nervous System. The nervous system of Laila cock- 
erelli is centralized in a manner similar to that of the typical 
Doridide. In the cerebro-pleural mass the fusion seems even 
greater than usual, so that when viewed from above no dis- 
tinction into cerebral and pleural ganglia can be made out, 
although on the under side two distinct lobes are visible. Below 
the posterior part of the cerebro-pleural are situated the pedal 
ganglia, which are well developed and joined to them by very 
short connectives. There are also a pair each of olfactory, 
optic, and visceral ganglia, making six pairs in all of supra- 
cesophageal, as well as the single pair of buccal ganglia, which 
are infra-cesophageal. The buccal ganglia are normally situ- 
ated most anteriorly, but their position relative to the rest of 
the ganglia varies with the position of the buccal mass, as 
the buccal ganglia have a fixed position close to the origin of 
the esophagus and so are moved forward and backward when 
the buccal mass is moved, while the other ganglia are com- 
paratively stationary. 
The buccal ganglia are ovoid, about 200 microns in the long- 
est diameter, joined to each other by a very short commisure, 
and to the cerebral by a long, slender connective that has its 
origin a short distance in front of the cerebro-pedal connective. 
They give off four pairs of nerves. Three of these enter the 
buccal mass directly, the posterior pair going to the region of 
the origin of the tongue. The fourth pair, which bear numer- 
ous minute ganglia, go upwards to the csophagus, and run 
backwards between it and the salivary glands, to which 
branches are probably given, and continue back to the liver 
mass, where they probably join the network of accessory nerves 
and ganglia, although this could not be positively determined 
in the specimens examined. This accessory system, which is 
described by Hancock and Embleton as covering the stomach 
and the lobes of the livermass in Doris, is very delicate in this 
