398 MONOORAPH OF THE AUSTRALIAN MA IlSIPOBIlANCUIT, 



cuspidate; disk with three strong unicuspid teeth anteriorly, 

 the basal pair followed by two or three similar teeth, the sides and 

 hinder portion with a series of broad tii- or bicuspid lamellae; a 

 row of small teeth inside the rim of the disk; tongue with two 

 pairs of narrow multicuspid plates inserted on its dorsal surface 

 and a finely cuspidate transverse plate below. Dorsal fin origina- 

 ting a short distance behind the middle of the body, divided into 

 two portions (in the adultj by a short interspace, the anterior 

 small, the posterior much larger and more or less continuous with 

 the caudal, which is free or nearly so. Tail moderate, the vent 

 situated well behind the middle of the second dorsal fin. No 

 conspicuous series of pores on the head or body. 



Etymology : — Mordax, voracious. 



Type: — MorJacia mordax, Gray = Petromyzon mordax, 

 Richardson. 



Distribution: — South-eastern Australia, Tasmania, and 

 Chile. 



The absence of this genus from the New Zealand fauna when 

 contrasted with its South American range is somewhat remark- 

 able. 



With regard to the propriety of retaining the generic name 

 Mordacia for these Lampreys in place of Caragola, which both 

 by a slight priority and by a more accurate diagnosis is fairly 

 entitled to selection, I cannot do better than to quote the opinions 

 of Drs. Gill and Boulenger as follows : — 



The former remarks {Proc. U.S. Nat. Mus. ISO^, p. 109):— 

 " In 1882 I used in preference the first name [Carayola) based on 

 a perfect individual. I have since been led to believe that the 

 precedence of one name by such a little margin as Caragola has 

 over Mordacia has no value, and that aptness of diagnosis, how- 

 ever desirable, is not necessary to procure priority, and I have, 

 therefoi'e, followed Dr. Giinther in accepting the name Mordacia 

 instead of Caragola." 



Dr. Boulenger writes {in lit.) : "I cannot agree with you that 

 the fact of one name appearing before another in the same book 



