.54 M. o. A. L, morch's review of the vermetid^. [Feb. II, 



evidently with a net ; the state of their sexual organs shows that 

 the spawning commences at that time of the year. It must be very 

 difficult to catch the fishes after the middle of November, partly be- 

 cause they retire into the deeper parts of the lake, and partly because 

 the attempts to set nets are frustrated by the stormy weather of the 

 season. Repeated endeavours to obtain more specimens, made by the 

 Earl of Enniskillen, proved to be unsuccessful. In a letter from 

 Mr. J. Walker, this gentleman mentions that he saw one taken with 

 a fly in the month of August. 



The Earl of Enniskillen mentions, in a letter directed to Mr. 

 Thompson, that the " Freshwater Herring" is plentiful in the middle 

 of November. " The people are now taking them in cartloads. 

 The flesh of such as I send is white and soft, and different from 

 what that of Charr is in any other lough." Mr. Thompson* saw 

 the female ; and, according to him, it is externally not different from 

 the male. The ovaria contained 959 ova in a specimen 11 inches in 

 length, each being two lines in diameter. 



Number of vertebrae sixty, as ascertained by Thompson in a male 

 and female fish, and by myself in two males. 



7. Review of the Vermetid^. By Otto A. L. Morch 

 (of Copenhagen). (Part III.) 



[Concluded from Proc. Zool. Soc. 1861, p. 365.] 



BivoNiA, Gray, 1850. 



The Bivirus, Gray, Cat. Brit. Mus. 1842, p. 62. 

 Bivonia, Gray, ibid. p. 90; Gray, 1850, in Mrs. Gray's Fig. iv. 

 p. 82. no. 3 ; Adams, Genera, i. p. 358. 



T. affixa, plerumque spiralis, apertura contractu circulari, scepe liris 



spiralibus interupto-nodulosis et lira mediana elevata ; columella 



IcRvissima, nitida. 

 Animal tentaculis cylindricis, filamentis pedalibus subulatis vel seta- 



ceis. Operculum parvum, rudimentare (Phil.). 



Dr. Gray gives (in the Brit. Mus. Cat. 1842, p. 62) the following 

 character : — " The Bivince have an orbicular spiral operculum, with 

 an oblong lateral scar like the Trochi." I suppose this description 

 was made from a broken specimen, giving the muscular impression the 

 appearance of being lateral. In the Brit. Mus. Cat. for 1840, quoted 

 in Proc. Zool. Soc. no. 258, by Dr. Gray, I cannot find anything 

 about this genus. The edition 1844, quoted in the same place, is, 

 according to the indication of the pages 62 & 90, no doubt a typo- 

 graphical error. In the Systematic Index of Mrs. Gray's Fig. of 

 MoUusca, p. 82, the diagnosis is altered thus : — "Operculum rudi- 

 mentary, small (spiral ?)," which is evidently taken from Philippi's 

 description of Vermetus triqueter, Biv., — " Operculum parvum, rudi- 

 taentare," which must thus be regarded as the type. Of the other 



■ * Ann. and Mag. Nat. Hist. 1841, vi. p. 443. 



