406 MONOGRAPH OF THE AUSTRALIAN MARSIPOBRAXCHII, 



and they adhere to it with an extraordinary and ferocious 

 tenacity." 



From the above quotation one gathers that prior to 1872 these 

 Lamprej^s were not only common in the Yarra, but tliat it was 

 an easy matter to study their habits there; how different it is at 

 the present day may be judged from the following : — " Mordacia 

 seems sporadic and very rare generally; we got a few floating 

 dead during the summer before last in the tidal Yarra " ( T. S. 

 Hall, in lit. July, 1896). 



In his Catalogue of Tasmanian Fishes (Proc. Boy. Soc. Tas. 

 1882, p. 1J/-1) Mr. R. M. Johnston records this Lamprey as 

 " abundant at certain seasons, clinging to the sides of perpen- 

 dicular rocks under mill-shoots, Cataract Gorge, North Esk, 

 Launceston; " and again {p. 62) speaking generally of the Tas- 

 manian species, " the Lamprey, though abundant in some rivers, 

 seems not to be in favour in the mai'ket, as they are rarely seen 

 there." Notwithstanding this alleged abundance I have found it 

 impossible to obtain a single specimen from the island. 



Total length to 450 millimeters. 



Type in the British Museum. 



In the preparation of this article I have been able to examine 

 seven specimens having a length of from 125 to 418 millimeters; 

 four of these were collected in the lower Yarra, and were kindly 

 forwarded to me by Sir Frederick McCoy (1) and Mr. T. S. Hall 

 (3) of the Melbourne University; two are in the Macleay Museum, 

 from the Nepean River and Tasmania respectively, and the 

 seventh, also from the Yarra, belongs to Mr. J. P. Hill of the 

 Sydney University. 



For the opportunity of seeing two ammoctetes I am also 

 indebted to the kindness of the latter gentleman, to whom they 

 were given by Prof. Baldwin Spencer. 



PBTROMYZONIDiE. 



Petromyzontid(e, Risso, Eur. Merid. iii. p. 99, 1826. 

 Fetromyzonidce, Bonaparte, Saggio, &c. p. 41, 1832. 



