several new species of Nudibranchiate Mollusca. 313 



rendered still more probable from the fact that the skin is a tissue 

 of cells, or perhaps is rather composed of a sort of network of 

 vessels running in every direction and uniting in two large trunks 

 that pass along the sides and pour themselves into the posterior 

 angles of the auricle. The blood that comes from the skin con- 

 sequently never passes into the true branchise. Cuvier, we are 

 aware, states that these vessels empty themselves into the gills. 

 With all deference to his high authority, we have convinced our- 

 selves after repeated dissections that such is not the case, but 

 that they go at once, as above stated, to the auricle. 



This fact is interesting, as it shows that even in those Nudi- 

 branchs which have the branchiae most perfectly specialized, only 

 a portion of the blood passes through the gill ; and when taken 

 in connexion with the anatomy of Dendronotus, and with the 

 peculiar form and internal organization of Eumenis, goes far to 

 establish the imity of the order Nudibranchiata. ^.^ 



Doris diaphana. Body not much depressed, equally rounded \ 

 at both ends, transparent yellowish white : cloak covered with 

 rather large clavate tubercles. Tentacles nearly linear, laminated 

 with eight oblique plates ; apertures without sheaths. Branchial 

 plumes eleven, simply pinnate, retractile within separate cavities, 

 set in an imperfect open circle. Head with a large veil. Foot 

 yellowish white, showing the liver through in a large dark patch. 

 Length nearly an inch. 



Under stones near low-water mark on Meadfoot sands, Torbay. 



This Doris approaches nearest to D. bilamellataj but has much 

 fewer plumes and is quite transparent and colourless. ^^^^ 



Doris pusilla. Body ovate, much depressed : cloak yellowish j 

 white, thickly freckled with dark brown spots, and having nume- 

 rous conical papillae obtusely pointed at the top. Tentacles long 

 and slender, pure white and finely laminated. Branchial plumes 

 nine, bea]itifully white, simply pinnate, set in an incomplete, 

 rather distant circle round the vent, and retractile within sepa- 

 rate cavities. Head with a broad veil. Foot rather broad. Length 

 about three lines. 



Under stones between tide-marks, Torbay. 



This pretty little species is not unlike D. depressa, but has the 

 papillse less slender. The plumes are fewer and form a smaller 

 circle, but are more conspicuous from their snowy whiteness con- 

 trasted with the darker colour of the cloak. ..^^ 



Doris subquadrata. Body rather elevated, white with a slight 1 

 yellowish tinge, semitransparent. Cloak small, scarcely covering ' 

 the head and foot, a little squared before and behind, mth the 

 edge slightly raised, not very convex, thinly covered with small 

 papillary tubercles. Dorsal tentacles finely laminated, retractile 

 within short smooth sheaths. Branchial plumes seven, non-re- 



