NUDIBRANCHIATA OF THE. L.M.B.C. DISTRICT. 137 
only a narrow basal tract free from them, (Pl. VI. fig. 9), 
in Ancula they are confined to the terminal one-third or so 
of the cerata. Possibly these glands, both in Polycera and 
Ancula, correspond to those found in a similar position 
in Aplysca (Pl. VII. fig. 1), viz., along the edges of the 
eplpodia. In Aplysia punctata, however, these epipodial 
glands are smaller and not so conspicuous, those of the 
under surface of the mantle edge being relatively larger 
and more numerous (Pl. VII. fig. 2). 
B. CERATONOTA (= CLADOHEPATICA.) 
Family Doronipé. 
Doto coronata, Gmelin. 
Dredged in Turbot Hole, off Puffin Island, August, 1889. 
With the view of determining the structure of the 
cerata, and especially the meaning of the little pigmented 
projections which give them their turretted appearance 
(Pl. IX. fig. 1), we have made a number of serial sections 
both longitudinal and transverse. The hepatic ceca in 
the cerata are very large and are branched and swollen, so 
that usually several large hepatic cavities are found cut in 
each section (Pl. [X. fig. 1).* Between the hepatic ceca 
and the ectoderm we find almost a continuous layer of 
eland cells which stain deeply with picrocarmine and are 
arranged in elongated clumps lying parallel with the 
ectoderm and usually two or three cells thick (Pl. IX. 
fig. 3, gl.). On the pigmented projections the columnar 
ectoderm is found to become rapidly cubical and then 
almost squamous (Pl. IX. figs. 2 and 4, &), while the dome- 
shaped cavity below the thin ectoderm is nearly filled up 
* For the general relations of the hepatic ceca in the cerata to the parts 
of the liver in the body see Herdman, Quart. Jour. Microse. Sci., vol. xxxi., 
p. 51, and pl. ix. 
