Prof. G. J. Allman on the Anatomy 0/ Actaeon. 161 



In accordance therefore with this arrangement, the Nudi- ^ 

 branchiate Mollusca will stand as follows : — 



ORDER. SECTION. FAMILY. GENUS. 



BranchisB in the mesiaH 



Liver compact 



Liver disintegrated.. 



line, placed in a circle I d^Hs, Polycera, 

 more or less complete f 0. 

 around the anus. 



DoRIDID^. -^ 



Branchiae arranged along! ^^.^^^. g j_ 

 the sides, or scattered. > i^^a, Thetis: 



TaiTONIADiE. J ' 



] 



'Branchiae papillose, orl Eolis, Alderia, 

 branched or muricated. > Dendronotus*, 

 EoLiDiD^. J Glaucus,&c. 



Branchiae foliaceous. "I Actaeon, Placo- 



AcT^oNiD^. J branchus? ^ 



EXPLANATION OF THE PLATES. 



Plate V. 



Fig. 1 . ActcBon viridis, viewed from above. 



Fig. 2. The same, viewed in profile. 



Fig, 3. The head seen from below. 



Fig, 4. Vascular system : a a, trunks which receive the blood from the pos- 

 terior parts of the branchial expansions ; b, circular vessel into 

 which the trunks a a open, and which also receives the blood from 

 the anterior part of the branchial expansions ; c, the ventricle. 



Plate VL 



Actceon viridis opened from above ; that portion of the hepatic ramifications 

 which occupies the right side has been removed in order to sim- 

 plify the figure, and for the same reason the ovaries ? have not been 

 represented on the left : a, buccal mass; 6, tongue; c, canal through 

 which the buccal mass opens exteriorly ; d, oesophagus ; e, stomach ; 

 /, intestine ; g g, anterior pair of salivary glands ; h h, posterior 

 pair ; i, pyriform sac opening into cesophagus ; k k, anterior trunks 

 of hepatic ramifications; I /, posterior trunks; m mm, culs-de-sac 

 in which the hepatic ramifications terminate ; «, ganglionic collar 

 of oesophagus; o, pharyngeal ganglia?; p, optic nerve; qr, nerves 

 running to tentacula and lips ; s, nerves supplying the digestive 

 system ; t, penis ; v, oval cavity in base of penis; w, vas deferens] 



* I would feel well-inclined to separate Dendronotus as the type of a 

 small family distinct from the true Eolididte. With Dendronotus 1 would 

 also join Data {Meltboea, Johns,), and then the second section of Nudi- 

 brauchs would consist of three families, of which the Dendronotida: would 

 be exactly co-extensive with the subfamily Meliboeince o^ Messrs. Alder and 

 Hancock. With the animal assumed by Rang as the type of his genus Jlle- 

 liboea, I am not sufficiently acquainted to decide upon its exact location. 



Ann, ^ Mag. N. Hist. VoLxvl N 



