124 MESSRS. ALDER AND HANCOCK ON 



stinctly angulated at the sides. Branchial plumes nine, small, simply pinnate, crimson, 

 forming nearly a complete cup ; the two posterior plumes smaller than the rest. Foot 

 large, broadly truncated in front, and extended to a blunt point behind. Length -niths 

 of an inch. 



One specimen only is preserved, which, from its diminutive size, may probably have 

 been young. 



Family DORIDOPSIDiE, Alder &; Hancock. 



Cloak large, without spicula or marginal appendages. Dorsal tentacles retractile 

 within cavities ; no oral tentacles. Mouth suctorial, opening on the front margin of 

 the foot, without tongue, jaws, or collar ; with a retractile proboscis. 



Genus Doridopsis, nov. gen. 



Body more or less depressed, ovate or elliptical. Cloak covering the head and foot, 

 smooth or with soft tubercles. Dorsal tentacles laminated. Head minute, generally 

 produced into small lateral lobes, without oral tentacles. Branchi8e plumose, wholely 

 or partially surrounding the vent on the medio-dorsal line, retractile within a common 

 cavity. 



The chief peculiarities in the anatomy of Doridopsis are found in connexion with the 

 alimentary system. In this genus there is no large rounded buccal organ, so constant 

 in the Nudihranchiata. On the contrary, we see here, in the place of that powerful 

 muscular apparatus, an attenuated suctorial tube or proboscis, which is capable of being 

 protruded through a small circular orifice situated in the anterior margin of the foot. 

 There is neither tongue, spinous collar, nor jaws, nor is there any armature whatever 

 in connexion with this proboscidiform mouth. It is furnished, however, with two large 

 folliculated glands, which pour their secretion through a slender duct into the anterior 

 extremity of the proboscis. The secretion thus supplied may perhaps be a solvent, to 

 enable the animal to penetrate the calcareous covering of its prey, and thus to reach its 

 food, or it may be a poisonous fluid to benumb its victims. From the position of these 

 organs, they might be supposed to be salivary glands ; but the true salivary glands are 

 present, situated as usual at the commencement of the CESophagus, though they are so 

 small as to be almost rudimentary. They are in the form of irregular masses placed 

 one at each side of the alimentary tube, just where it joins the posterior extremity of 

 the proboscis. At this point the oesophagus is somewhat constricted, but it almost 

 immediately enlarges into an elongated anterior stomach or crop. On reaching the 

 anterior border of the liver it is again contracted a little, and, penetrating that viscus, 

 it opens into the true stomach, which is of considerable extent. The liver itself is bulky^ 



