248 Mr. J. Gwyn Jeffreys on Dredging 



All these I will now notice as regards the Mollusca. Other 

 branches of the marine Invertebrata will be treated of by 

 Mr. Norman, Mr. Waller, and Dr. M'Intosh ; and Dr. Giinther 

 has kindly promised to report on a few small fishes caught in 

 the dredge. 



1. New Species. — The species I am about to enumerate are 

 new to the British fauna, but not to science. 



Terehratella Spitzbergensis, Davidson. 



A fresh and perfect, although dead, specimen occurred in 

 80-90 fathoms off Unst. The only locality hitherto recorded 

 for this shell in a living state is Spitzbergen. It was found by 

 Hisinger and myself in a fossil state at Uddevalla, and last year 

 by Messrs. Crosskey and Robertson in another raised sea-bed 

 near Christiania. There is, of course, a possibility that the 

 Shetland specimen also may be fossil; but it has all the appearance 

 of being recent ; and Terehratula cranium and T. caput-serpentis 

 (both of which are likewise arctic species) live in the same place 

 where this specimen of Terehratella Spitzbergensis was dredged. 



Rhynchonella psittacea, Gmelin. 



A specimen (unfortunately broken in dredging) was found 

 with Terebratella Spitzbergensis, Terebratula cranium, and T. 

 caput-serpentis. This was filled with soft mud, in which was a 

 fresh, but dead, young specimen of R. psittacea. I had on a 

 former occasion dredged a full-grown specimen and a young one 

 (both quite perfect, although not living) off Unst. In ' British 

 Conchology,^ vol. ii. pp. 22 & 23, is an account of all the speci- 

 mens said to have been taken by Capt. Laskey and others in the 

 British seas; and I am still convinced that most of these re- 

 ported discoveries were mistakes, and that some of the speci- 

 mens are fossil. The present case is free from doubt, except 

 on the latter ground. Single valves of Pecten Islandicus, Tellina 

 calcaria, and Mya truncata, var. Uddevallensis, are not uncommon 

 on the northern and eastern coasts of Shetland, and were procured 

 with T. Spitzbergensis and 7^. psittacea ; but the former had 

 an unmistakeably fossilized or chalky aspect, and never were 

 perfect or had the valves united. It seems to be an established 

 rule that all marine invertebrate animals increase in bulk north- 

 wards ; and thus the comparative size of living and dead speci- 

 mens of arctic species found in the Shetland seas may serve as 

 an additional test to distinguish which of the latter were re- 

 cent and which fossil. The two Brachiopods in question must, 

 I think, stand or fall together as British. Mr. Davidson (the 

 great authority on this abnormal class of the Mollusca) says 



