Revision of the Genus Lomanotus. 211 



taken in the Bay of Naples at a depth of 40 metres in 

 association with the common hydroid Antennularia ramosa, 

 and the younger individual was kept alive in an aquarium 

 and nourished on the hydroid for the space of a month. 

 Trinchese, struck by the peculiar aspect of the adult animal 

 \^2 inch long (he speaks of it as " singolarissimo '*), gives a 

 full description of its outer features, with some anatomical 

 details, and proposes for the new Lomanotus the name 

 L. eisigii. In its general features, as here described, 

 L. eisigii agrees very closely with Verany's L. genet, but the 

 peculiar caudal extension of its pleuropodium at once distin- 

 guishes it from Verany's and from all other previously 

 described species of the genus. The following is a close 

 rendering of the passage in which Trinchese describes the 

 pleuropodium of L. eisigii : — 



On each side of the back is placed vertically a thick mem- 

 brane, which, beginning at the outward side of the base of 

 the rhinophore, ends near the apex of the tail. Here the 

 membrane of one side uniting with that of the other forms a 

 broad fin, which is the principal swimming-organ. The 

 posterior margin of this fin is furnished with small triangular 

 papillse. (" Quivi la membrana di un lato unendosi a quella 

 delfaltro forma una larga pinna che e 1' organo principale del 

 nuoto. II margine posteriore di questa pinna e munita di 

 piccole papille triangolari.") 



The margins of the rhinophore-sheaths are described as 

 having five unequal papilla?, the body is transparent white 

 marked with irregular opaque white blotches and red dots. 

 The tips of the papillae on the head, on the sheath-margins, 

 on the pleuropodium, and on the caudal fin are opaque white, 

 the upper third of their length being orange-yellow. 



In the second section of his paper, entitled " Descrizione 

 dell' individuo in via di sviluppo/' Trinchese traces the 

 development of the young specimen which he nourished for a 

 month on the ccenosarc or living substance of Antennularia. 

 The importance of the observations here recorded and the 

 probability that Trinchese's paper may have been overlooked 

 by students of the nudibranchs in this country will, perhaps, 

 justify the somewhat lengthy extracts from it now given. 



At first, says Trinchese, this individual had a form so 

 different from that of the adult that I took it for a young 

 member of the family of the Eolididse. From the anterior 

 margin of the head sprouted two short tentacles, and behind 

 these rose the two rhinophores, laminated for almost their 

 whole length and entirely destitute of sheath. On each side 

 of the back were fixed four conical papilla? disposed in a 



