GASTEROPODA. DORIDIDZ. 17 
The nervous system of the indigenous genera consists of 
twelve pairs of nerves, and a brain, which is situated anteriorly. 
The first pair of nerves arises from the dorsal tentacula ; the 
second from the tube which forms the mouth ; all the others 
(excepting the eleventh and twelfth, which arise from the 
stomach and its vicinity, the first forming two lateral ganglia, 
the twelfth completing the nervous collar) from the hinder and 
lateral muscles. 
The stomach is very thin, and the other parts of the intes- 
tinal canal short. The liver is very large ; and has in contact 
with it a gland that secretes a liquor which passes out by a 
tube opening on the left of the anus, within the circle of 
branchiz. 
The Dorididz inhabit the sea, especially on rocky coasts, 
where they may be found on the recess of the tide. They are 
occasionally taken by the dredger in deep water, and are more 
rarely thrown ashore by storms on some of our sandy coasts. 
Synopsis Generum. 
Dorsum appendicibus supplementariis nullis. Pes 
posticé obtusus . . .. <5. Dori 
Dorsum ante tentacula dorania appendicibus 4, et 
pone branchias appendicibus 2 instructum. Pes 
postice aeuminatus~.°. 2) 2° Lo Lee oe. 6. Coma 
Genus 5. Doris. 
Doris, Auctorum. 
Dorsum appendicibus nullis instructum. Pes postic® ob- 
tusus. 
Synopsis Specierum. 
* Dorso lateribusque crebreé verrucosis. 
1. Montagui. Corpore depressiusculo, verrucis planis, bran- 
chiis 8-radiatis. 
2. Britannica. Corpore convexo, verrucis plano-convexis, bran- 
chiis 10-radiatis. 
3. vulgaris. Corpore convexiusculo, verrucis prominentibus 
convexis, branchiis 14-radiatis. 
