BY J. DOUGLAS OGILBY. 403 



Dr. Gray, when engaged on his Catalogue of Chondropterygians 

 rightly removed the Tasmanian species from that genus under the 

 name Mordacia, and further proposed for a very similar Chilian 

 Lamprey the name Carago/a lapicida, the generic differences 

 relied on being due to the defective dentition of the former. 



In 1863 Philippi (Wiegm. Arch. p. .207, pi. x.f. b.) described 

 and figured a Chilian species under the name of Petromyzon 

 anwandteri, and in the following year (I.e. p. 107, and Ann. & 

 Mag. Nat. Hist. 3rd. ser. xvi. I860, p. 221) described yet another 

 species from the same territory as P. acutidens. 



All these various forms, Tasmanian and Chilian, were united 

 together by Dr. Giinther in 1870 under the common name Mor- 

 dacia mordax, a conclusion which — seeing that he had but a 

 single example from each so widely separated locality, and that 

 one of these (the Tasmanian) was admittedly in bad condition — 

 is so manifestly inconsiderate that I prefer to regard the Chilian 

 form distinct from that described by Richardson until conclusive 

 evidence to the contrary shall have been brought forward.* 



Breeding : — The habits of the Shoz-t-headed Lamprey during 

 the breeding season are quite unknown, but it is not probable 

 that they differ in any marked degree from those of the more 

 carefully studied arctogaean species. 



In the typical genus Petromyzon the eggs are minute, of 

 spherical form, and number many thousands; the ova and sperm 

 fall first into the body cavity and are emitted from thence through 

 the abdominal pores; each ovum is enclosed in a delicate gelatinous 

 membrane ; fertilization takes place in the water after extrusion; 

 and the eggs arrive at maturity simultaneously after the lapse of 

 about a fortnight. 



An interesting account of the spawning habits of a species of 

 Pfitromyzon is given by Prof. McClure and Dr. Strong, from 



• "Less confusion arises from calling them" — i.e.., species from remote 

 districts — " ditferent until shown to be the same, than from calling them 

 alike until shown to be differeut " [David S. Jordan, in lit.). 



