A HUMP-BACKED TROUT FROM STRANRAER 227 



to missing centra, have become attached. The deficiency in 

 the internodes would in this case be due to the actual 

 absence of centra. (2) The alternative is that the 

 skeletogenous tissue of the future centra having been com- 

 pletely formed a compression in certain regions took place 

 succeeded by continuous ossification, uninterrupted by nodes. 

 Such an interpretation would mean that in the Stranraer 

 specimen, the abnormal internodes contain the elements 

 of as many centra as they bear neural spines, but that 

 those elements had not the opportunity of developing into 

 separate centra. In the case of either of these alternatives 

 it seems likely that the origin of the malformation lay 

 deeper than environment, that it must be referred back to 

 congenital variation. 



NATURAL HISTORY DEPARTMENT, 



THE ROYAL SCOTTISH MUSEUM, EDINBURGH. 



NOTES ON NUDIBRANCHIATE MOLLUSCS. 



By RICHARD ELMHIRST, F.L.S., 

 Superintendent of the Marine Biological Station, Millport. 



THE following notes contain some records of new localities 

 in the distribution of Nudibranchs in the Clyde sea area, and 

 two species, Doto pinnatifida and Lamellidoris luteocincta^ 

 new to the Clyde list as given in the " Fauna, Flora, and 

 Geology of the Clyde Area," 1901; also some observed times 

 of spawning. 



The following abbreviations are used : sp. = spawn found 

 under natural conditions ; sp. cap. = spawned in captivity. 



Eolis papillosa (L.), sp. Feb. to May. 



Cuthona nana (A. and H.). Kyles of Bute. Mating and sp. cap. 



-Sept. 



Eolis olivacea (A. and H.). Off Keppel Pier, Cumbrae. 

 Tergipes despectus (Johnst). Near the Marine Station. 



Embletonia pulchra (A. and H.). One specimen dredged off the 

 station had none of the usual red colour, but was marked with 

 the normaNopaque white spots. The cerata were unusually 

 large. 



