KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 41. NIO 4. Ö 



1. Gills absent: anus lateral on the right side Fam. DoridoxidcB. 



2. Gills surrounding the dorsal anus, 



a. nearly always retractile; anterior tentacles usually present, digitiform or 

 conical (Cryptobranchia) Fam. Dorididce. 



b. never retractile; tentacles lobe-shaped or replaced by a velum (Phanero- 

 branchia). 



+ . Pharynx without ingluvies; mantle-margin prominent or not, mostly 



with cirri (Non Suctoria) Fam. Polyceridoi. 



+ f . Pharynx with an ingluvies at the upper side; mantle-margin generally 



prominent with or without cirri (Suctoria) Fam,. Goniodorididce. 



C. Aeolidoidea (Cladohepatica) : Heart in the median line; male and female porus ge- 

 nitalis united to one orifice; vagina with a receptaculum seminis only; liver rami- 

 fied; no blood-gland; anus usually lateral; mandibulse present, lateral. 



1. The back with papillse, enclosing the liver -lobes. 



a. Oral tentacles present; rhinophores without vaginse, not retractile; papillae 

 usually claviform or cylindrical, mostly with cnidocysts Fam. Aeolididce. 



b. No oral tentacles ; rhinophores retractile within wide vaginse ; cnidocysts 

 absent; papillse with rings of minute tubercles, in one series on each side; 

 foot with the anterior angles rounded: margin of the mandibulse smooth; 

 anus lateral; penis unarmed Fam. Dotonidce. 



2. The back without papillse ; tentacles = broad side-lobes of the anterior part 

 of the head; back flattened or slightly convex; rhinophores with laminated 

 clubs, retractile within short sheaths ; radula oo . 1 . oo . 



a. Gills lamelliform on the under-si de of the prominent pallial margin 



Fam.. Pleurophyllidiidce. 



b. Gills absent Fam. Pleuroleuridce. 



D. Blysoidea (Ascoglossa) : Heart and liver as in Aeolidoidea; male and female porus 

 genitalis separated; vagina with both spermatocyst and receptaculum seminis; 

 pharynx on the under-side Avith a sac, receiving the worn teeth: mandibulse ab- 

 sent; ganglia 7, separated, connected by commissures. 



1. The sides of the back with leaf-like or club-like processes (Cirrobranchia) 



Fam. Hermceidce. 



2. The sides of the body forming broad lobes, containing the liver-branches 

 (Pterobranchia) Fam. Elysiidce. 



3. Body smooth, slug-like, without processes and lobes (Abranchia) 



Fam. Limapontiidce. 



K. Sv. Vet. Akafl. Haii.ll. Ban.l 41. N:o i. 



