Cheeseman. — On Nudibraucbiate MoUusca. 213 



A careful examination of tbe fisb sbows, however, tbat it must be 

 classed as a true sea or salmon trout, although, as has been found invariably 

 to be the case in Otago specimens, it presents a certain admixture of the 

 characters of the many species into which the sea trouts from the various 

 rivers in Europe have been subdivided. 



The specimen proves to be a female that has just spawned. For the 

 length of twenty-five inches its weight, four pounds, is small, but it is 

 evidently lanky and out of condition, as otherwise it would have been a six 

 pound fish. The stomach contained half-digested remains of a young 

 barracouta (Thyrsites atun) and a sea mullet ( Agonostoma forsteri), each 

 about nine inches long, proving that it must have been feeding voraciously 

 in salt water. The importance of this determination is due to the fact 

 that the only salmon trout ever introduced to New Zealand were bred from 

 a small lot of ova that came from Tasmania, in 1870, and of which the 

 original stock, turned out in Shag Eiver, Otago, did not exceed seventy or 

 eighty fish. What are supposed to be the progeny of these now abound on 

 the Otago coast, and this discovery might seem to point to its having 

 spread in its migration round the coast as far as Blind Bay. On the other 

 hand, it might be suggested that what we know as brown trout in the rivers 

 are of the large fast-growing variety known as the Thames trout, but 

 which, in New Zealand, enter the sea and acquire the characters of the true 

 sea trout. 



Art. XXVIII. — On two Species of Nudibranchiate Mollusca. 

 By T. F. Cheeseman, F.L.S, 

 [Read before the Auckland Institute, 5th,- September, 1881.] 

 Doris luctiwsa, n.sp. 

 Length 1-2 inches. Body oblong or linear-oblong, back moderately 

 rounded. Mantle small, rather narrow and hardly concealing the sides 

 of the foot, smooth and soft to the touch, of a dirty flesh-brown more or less 

 spotted or streaked with reddish-brown ; occasionally dirty white with a 

 few reddish-brown markings. Towards the sides of the mantle the reddish- 

 brown markings are often arranged in more or less interrupted lines. 

 Dorsal tentacles (rhinophores) stout, clavate, completely retractile within 

 raised sheaths, strongly laminate, laminae over 20 in number. The lamina 

 are blotched with dark purple and greenish-yellow, the tips of the sheaths 

 are usually greenish-yellow. Branchiae 6, rarely 6, forming an incom- 

 plete circle round the tubular anus, bipinnate or tripinnate, rounded at 



