NUDIBRANCHIATA. 
2 1 o 
Length of specimen (from spirits) 3 lines ; body broadly truncate ante- 
riorly, tapering to the tail ; tentacula lamellated ; 3 branchial filaments ; 
eyes two, at the inner side of the posterior base of the tentacula. Colour 
whitish, with the frontal processes of an orange-yellow ; a few scattered 
dots of this colour on the mantle. 
Although the four black lines described by Muller as extending in an 
interrupted manner along the body of P. quadrilineata are entirely want- 
ing in my specimens, I cannot, possessing as they do every other character 
in common with it, regard them as of a different species. They are at 
the same time quite distinct from the supposed varieties of P. quadrilineata 
figured in table 138 of the Zoologia Danica. 
Three individuals of this species occurred to us on the same occasion 
as the Tritonia lactea , when dredging at the entrance of Strangford Lough ; 
they were adhering to Laminaria digitata. When placed in a phial of 
sea-water, they were generally to be seen suspended by their threads from 
the surface, the body at the same time moving freely about with much 
grace. This species has hitherto been unnoticed in the British seas. 
P. typica , mihi. 
P. with 4 frontal appendages, tapering towards the point ; tentacula 
lamellate ; branchial lobes very large. 
Length 5 lines ; body narrow ; tail tapering ; branchial filaments 
elongated, in a tuft anterior to the lobes ; disk thin and flexible at the 
edges. Colour whitish, tentacula and branchial lobes tipped with yellow ; 
back and sides thinly studded with tubercles (spots ?) of a yellow colour, 
three of which are in the middle of the back, and six or seven close to the 
tuft of branchial filaments ; the intestines (seen through the skin) of a 
dark colour. 
Of this well-marked species, two individuals were dredged in Strangford 
Lough by Mr. Hyndman and myself, in January, 1835, at the same time 
with Euplocamus plumosus. They seemed partial to coming to the surface 
of the water in which they were for some time kept, and to moving along 
with the foot upwards. 
P. ocellata , Aid. and Hanc. 
Mr. Alder, by means of the dredge, took this species commonly, and of 
all sizes, in Dublin Bay, in August last, and subsequently obtained a 
specimen at Malahide. 
P. citrina , Alder. 
Mr. Alder dredged two or three specimens of this species in Dublin 
Bay, at the same time with the last. 
P. cristata , Alder. 
Obtained with the preceding two species : common. 
Genus ^Egirus. 
2E. punctilucens, D’Orbigny. 
Professor Allman obtained this Polycera in a pool at Courtmasherry 
Harbour, County Cork. 
Genus Euplocamus. 
E. claviger, Mull. sp. 
Body elongated, tapering to the tail ; three plumose branchial filaments. 
t 2 
