﻿RECENT AND TERTIARY BRACHIOPODA. 7 



Mr. Jeffreys gives the following habitats : — Orkneys, 35 to 40 fathoms (Thomas); 

 East Shetland, Skye, Co. Antrim, Moray Firth (Dawson) ; Dublin Bay (Waller) ; 

 Exmouth (Barlee and Clark) ; Guernsey (Lukis and Jeffreys). It occurs also in the 

 Mediterranean. Fossil in the Pliocene. 



10. Argiope decollata, Chemnitz. Dav., Supplement, PI. I, figs. 5, 5 a, and 6. 



Anomia decollata, Chemnitz. Conch. Cab., viii, p. 96, pi. kxviii, fig. 705. 

 Argiope — Jeffreys. Brit. Conch., p. 18, vol. v, pi. xix, fig. 3, &c. 



Mr. Jeffreys dredged a few specimens of this species two miles east of Guernsey in 

 18 fathoms, which, as he justly observes, is the most northern limit that has been 

 discovered for the present species. In the Mediterranean it is a common shell at a depth 

 of from 20 to 60 fathoms. On Adventure Bank in 92 fathoms. 



A. decollata occurs fossil in the Pliocene rocks of Sicily, the south of France (Nice), 

 and several other places. 



11. Atretia gnomon, Jeffreys. Dav., Supplement, PI. I, figs. 7 — 10 a. 



Cryptopora gnomon, Jeffreys. Nature, Dec. 2, p. 136, 1869. 



Atretia — Jeffreys. Preliminary Report of the Scientific Exploration of 



the Deep Sea in H.M. Surveying Vessel ' Porcupine,' 

 Proc. R. Soc, No. 121, p. 421, 1870. 



Mr. Jeffreys obtained only a few imperfect specimens of this curious species, 

 and consequently was unable to give a complete description. All he states is, that 

 " Among the Mollusca were valves of an imperforate Brachiopod, with a septum in the 

 lower valve, which we propose to name Atretia gnomon" Off the north coast of Ireland 

 in 725 and 1443 fathoms. 



I have, through the kindness of Mr. Jeffreys, been able to examine and, as it were, 

 restore the shell from the fragments he had been able to assemble. One point only 

 remained uncertain, namely, whether when perfect there were two little curved plates 

 attached to the upper surface of the septum ; for if such were the case then it would 

 nearly agree with the Mannia Nysti of Dewalque, a fossil species from the 1 Crag gris ' or 

 Stage Scaldisien of Antwerp, in Belgium. M. Dewalque did not publish any description 

 of his shell, but named it as above in his ' Prodrome d'une description geologique de la 

 Belgique,' p. 432, 1868. In Atretia the shell-structure is fibrous and without perforations, 

 as in Rhynchonella (?) ; it will be more fully described by Mr. Jeffreys when more perfect 

 material shall have been dredged. 



