BY J. DOUGLAS OGILBY. 399 



constitutes priority, and it would be a pity to alter the well 

 known name Mordacia to Carayola.^^ 



It is only in deference to the opinions as expressed above, of 

 two so eminent scientists, that I have decided to adhere to the 

 more generally accepted name Mordacia; nevertheless it is due 

 to myself to say that the substitution of that name for Garagola 

 is distinctly repugnant to me; so long as the rule remains in force, 

 which provides that the earliest name, all other requirements 

 having been complied with, shall take precedence, I cannot 

 coincide with the contention that the accident of two names 

 being published in the same volume, or even, as in this case, on 

 the same page of the same volume, can under any circumstances 

 justify our rejection of the earlier in favour of the later name; 

 by so doing we are assisting to open a rift which may in course of 

 time imperil the stability of the entire fabric; while the plea that 

 a name should be retained because it is better known is sentimen- 

 tal and unsound, and therefore unworthy of consideration. 



As is the case with all the Lampi^eys the dentary plates are 

 provided with a horny covering, which may easily be removed in 

 layers, but except for the necessary decrease in size both of plate 

 and cusps consequent on the i-emoval of each separate layer, no 

 altei'ation in their appearance is noticeable, unless the entire 

 corneous lamina be lost, and the underlying papillary prominence 

 be thus exposed to view. 



Gray's description of Mordacia was based on a specimen from 

 Tasmania, the dentition of which was imperfect through the loss 

 of the corneous lamellte of many of the plates, while his type of 

 Caragola was a Chilian example in which the lamellte were intact; 

 the diagnosis of Garagola is therefore more correct; surely an 

 additional argument for the x'etention of that name. 



8ome interesting i-emarks on the pineal eye in this Lamprey, 

 from the pen of Prof. Baldwin Spencer, will be found in the 

 Proceedings of the Royal Society of Victoria, Vol. ii. 2nd Series, 

 p. 102, 1S90. 



