518 On two new British Nudihranchiate Mollusca. 



such a narrow point behind, the branchiae extend so far back 

 that the extremity of the tail is less seen, perhaps, than in 

 any other species except EoUs glaucoides, A. & H. 



Lomonotus Hancocki, n. sp. 



Body elongated, of a very light pinkish orange tinge, very 

 transparent, so that the internal organs are clearly seen 

 through the skin ; white, the front margin of the foot micro- 

 scopically sprinkled with red specks. Veil with two tenta- 

 cular processes on each side, overhanging the mouth ; these 

 processes are orange-coloured below, and above are micro- 

 scopically sprinkled with red in the same manner as the 

 margin of the foot. Tentacles terminating above in a calyx- 

 shaped expansion, formed of five leaflet-like points, from the 

 middle of which rises the small, conical, smooth termination 

 of the tentacle ; this conical process is of small size, not 

 exceeding that of the divisions of the calyx-like sheath. Bran- 

 chial processes in the form of a waved raised curtain, sur- 

 mounted by flat triangular papillas, passing down each side 

 of the back and uniting behind ; the undulations of the cur- 

 tain consist of three outward and four inwardly directed folds 

 on each side ; the fold which is nearest to the head is the 

 largest ; the papilla on this fold are 18-20 in number ; the 

 jjapillse on all the folds vary considerably in size, but there 

 appears to be always one larger than the rest; they are capable 

 of contraction and dilatation, and are constantly changing their 

 apparent dimensions while the animal is in motion ; they are 

 banded with deep dark orange, while the small points in 

 which they terminate are pale orange. Length 2j inches. 



I dredged a single specimen of this very fine Nudibranch 

 off Berry Head, Torbay, June 25, 1875. 



It approaches both L.flavidus^ A. & H., and L.portlandi- 

 cusy Thompson, but differs apparently from both in many 

 particulars, and especially in the form of the tentacles, which 

 have a very marked character in the small size of the terminal 

 simple conical process which is projected beyond the calyx- 

 like sheath. 



I have named this species after Mr. Albany Hancock, the 

 joint author with Mr. Alder of the great master- work on the 

 Nudibranchiata — the latter unsurpassed in intelligent discri- 

 • mination and just appi'eciation of the value of morphological 

 characters, the former a prince among marine invertebrate 

 physiologists. Much as any student must admire the excel- 

 lency of Mr. Hancock's work, as evidenced in the elaborate, 

 clear, and comprehensive exposition of the anatomy and phy- 

 siology of the Nudibranchiata, Brachiopoda, &c., it is only 



