480 Mr. Thompson's Additions to the Fauna of Ireland. 



The distribution of the Silurus Giants on the continent of Europe 

 is somewhat anomalous, as I learn from M. Agassiz. In Central 

 Europe it is found in the lakes of Neuchatel, Bienne, and Morat 

 only : — in no other lakes or rivers connected with the Rhine does it 

 occur. It inhabits the rivers flowing into the Baltic and Black Sea. 



MOLLUSCA. 



Tritonia bifida, Flem., Brit. Anim. 



Doris bifida, Mont., Linn. Trans., vol. xi. p. 198. t. 14. f. 3. Au- 

 gust 25, 1840. — An individual of this species taken by Mr. Getty 

 and Mr. Hyndman, when dredging in Belfast Bay, was brought 

 to me. It agrees critically with Montagu's description, except 

 in the following points. There are just 12 appendages on each 

 side, three of which are larger than the rest, but placed at un- 

 equal distances from each other on both sides, and not opposite 

 as shown in Montagu's figure. The colour is better defined 

 than in the figure ; the marginal line, whence the appendages 

 issue, is strongly marked and reddish, as they likewise are ; foot 

 plain flesh-colour. 



The animal is extremely agile, and planaria-like is one mo- 

 ment twice the length it is the next ; it often moves about with 

 the foot upwards, and in its motions several times had the long 

 tail thrown quite under the head. 



Meliboea fragilis , Forbes, Malacologia Monensis, p. 4. pi. 1. fig. 4. 

 July 20, 1840. Three examples of this species were taken on 

 Antennularia antennina, dredged in Clew Bay (co. Mayo), by 

 Mr. R. Ball, Mr. Forbes, and Mr. Hyndman. 



Eolidia Zetlandica, Forbes, Athenaeum, 1839, p. 647. July 29, 1 840. 

 This species was taken by Mr. Forbes and myself between tide- 

 marks at Lahinch, county Clare. 



Euplocamus pulcher. (See Annals Nat. Hist., vol. v. p. 91. note.) 



Tergipes pulcher, Johnston, Mag. Nat. Hist., vol. vii. p. 490. f. 59. 



Triopa claviger, Johnston, Annals Nat. Hist., vol. i. p. 124. At the 

 same time with the Eolidia Zetlandica, an individual of this spe- 

 cies occurred to us. 



Chiton liBvigatus. Obtained in Strangford Lough by Mr. Hyndman 

 and myself. On oysters brought to Belfast market from Car- 

 lingford and Greencastle (co. Londonderry), W. T. ; Bangor, 

 CO. Down, Mr. R. Patterson. 



** Pleurobranchus plumula. Malbay (co. Clare), very rare," W. H. 

 Harvey, Esq. 



Turritella subtruncata. 



Turbo subtruncata, Mont., p. 300. t. 10. f. 1. Of this species a single 

 specimen was obtained at Bundoran (co. Donegal), in 1840, by 

 Mrs. Hancock. 



Rissoa calathisca. Among shell -sand which I obtained at Bantry 

 Bay in 1834, was an individual of this species. 



Rissoa rupestris, Forbes, Ann. Nat. Hist., vol. v. p. 107. pi. 2. f. 13. 

 Dublin coast, T. W. Warren, Esq. ; North-east coast, Mr. 

 Hyndman and W. T. Not rare. 



