692 



REV. R. BOOa WATSON" OX THE 



Fleming observed, "I would venture to suggest that il> is only 

 a variety of Gadus morrliua.^'' 



It agrees with Gadus macroceplialus, Tiles. ; but unfortunately 

 that author does not record the number of fin-rays. However, 

 the length of the head, size of the eye, extent of the upper jaw, 

 and the elongated ventral ray are the same. Tilesius's example came 

 from Kamtschatka ; Kner and Steindachner's from Decastris Ba3^ 

 . Gadus callarias (Blocli), Grrifiith in Cuv. Animal Kingdom, x. 

 p. 484, may be this species, which he observes has the upper jaw 

 longer than in Gadus morrliua ; but such is not shown in Bloch's 

 figure, which appears to represent the Common Cod. 



The Lord-fish " of Yarrell appears to difter from this specimen 

 in the eye being smaller and the upper jaw shorter ; but it must 

 be remembered that only a coloured figure was kept. The number 

 of rays in the fins of fishes of this genus are subject to consider- 

 able variation ; but if Turton's, Yarrell's, Kner and Steindachner's, 

 and the present form are examples of the same species, the latitude 

 must be very wide indeed. 



PLATE XIV. 



Morrhua macroccphcda, reduced sketch of the specimen obtained at the 

 mouth of the Thames, 1879. 



MOLLUSCA OF H.M.S. ' CHALLENGER ' EXPEDITION. 



IV. TROcniDiE continued, viz. the Genera JBasilissa and TrocJius, 

 and the Turbinid^, viz. the G-enus Turho. By the Eev. E. 

 BooG "Watson, B.A., F.L.S., &c. 



[Published by permission of the Lords Commissioners of the Treasury.] 



[Read June 5, 1879.] 



The JBasilissa oxytropis which follows did not present itself in 

 time to be included in the previous list. 



Of the Trochus group the Margaritas are many of them remark- 

 able for beauty and for form. 



The Turbos are very few ; but one is of extraordinary beauty. 

 . All the species now communicated are new. Some are from 

 very deep water. All throw light on a marine zone not yet 

 familiar. The list of known species presents no such features of 

 interest as to call for its publication at present. 



