92 Mr. Thompson on the Mollusca of Ireland. 



" Polyctra quadriUneata" var. norUineata. PL II. fig. 6**. 

 Doris qttadrilineata, Mull. Zool. Dan. vol. 1. p. 18. tab. 17« 

 fig. 4— C>. 



Frontal processes of the mantle 4, angles of the foot produced ; 



pair of branchial lulus rather small. 



Length "i" specimen (from spirits) 3 lines; body broadly truncate 

 anteriorly, tapering to the tail; tentacula lamellated ; 3 branchial 

 filaments ; eves 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 ex- 

 tending in an interrupted manner along the body of P. qua- 

 drilineata, are entirely wanting 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. quadri- 

 Uneata figured in table 138 of the c Zoologia Danica.' 



Three individuals of this species occurred to us on the same 

 occasion as the Tritonia luctea, when dredging at the entrance 

 of Strangford lough ; they were adhering to Laminaria diyi- 

 tata. 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. 



Polycera typica, mihi. Plate II. fig. 5. 



P. with 4 frontal appendages, tapering towards the point ; tenta- 

 cula 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 



* The figure is necessarily stiff, having been drawn from a dead specimen. 

 Muller '8 was done from the living animal. 



