TWO RARE BRITISH NUBIBRANCHS. 159 



pleuropodial lobes (compare Triuchese's figure of Govia rubra). Body 

 widest behind the head, gradually tapering posteriorly. Head with 

 an oral veil bearing four papillae on each side, the second anterior 

 one being the largest. These papillae were constantly changing their 

 shape during life, as Gosse and Trinchese have recorded. Rhinophoral 

 sheaths erect, cylindrical, the margin subdivided into about ten 

 rounded projections. This agrees closely with the figure and descrip- 

 tion of the sheaths of Govia viridis. Those of G. rubra, on the other 

 hand, have plain margins. Rhinophores with a rounded, bulbous, 

 laminated base, terminating above in a smooth columnar tip. Pleuro- 

 podium produced into four lobes on the right and five on the left, the 

 fifth being rudimentary. The first pair of lobes are opposite, the 

 rest gradually becoming alternate, as in Trinchese's figure of Govia 

 rubra. Each lobe is concave externally and is composed of seven 

 papillae, one being dorsal and median, three anterior, and three 

 posterior. The foot is rounded anteriorly, posteriorly it ends in a 

 slightly bifid tail, as in Govia (Trinchese, loc. cit. p. 183 and my 

 fig. 1). The anal papilla very small, cylindrical, situated half way 

 between the first and second lobes of the right side. Genital opening 

 near dorsal surface between the rhinophore and the first dorsal lobe of 

 the right side. 



In the appended table I have compared the different specimens of 

 Hancochia and Govia. Although they all agree in main points, no two 

 individuals do so in detail. 



