8 



Records of the S.A. Museum 



EPIGONICHTHYS AUSTRALIS Raff (S. Australian Lancelet). 



Asinnmetron australis Raff, Endeavour Res., i, liJ12, p. 303, pi. xxxvii, fig. 1-7 

 ( structure ) . 



CRANIATA. 



Class CYCLOSTOMATA (Lampreys). 



a. A single median suproral lamina, developed from 

 the upper arch of the annular cartilage, 



mouth fringes present Petromyzonidae 



aa. Two distant lateral laminae developed, mouth 



fringes rudimentary Caragolidae 



Family PPZTROMYZONIDAE. 

 GEOTRIA Gray, 1851 (australis). 



GEOTRIA AUSTRALIS Gray (Wide-mouthed Lamprey). 

 Gcotria austraUs Gray, Chondropt., 18r)l, p. 142, pi. ii and P.Z.S., 18ol, p. 239, 



pi. iv, fig. 3 and pi. v; Ogil., P.L.S., N.S.W., xxi, 1896, p. 422. 

 Geotria allportii Giinth., P.Z.S., 1871, j). 675, pi. Ixx. 





Pig. 3. 



Gt'olria (iK.slraJis. 



Lampreys are eel-shaped animals which undergo a metamorphosis; in the 

 earlier stages the eyes are rudimentary and teeth are entirely absent. When 

 adult these i)arasites attach themselves to fishes and rasp off the flesh by means 

 of Ihi- horny teeth with which the circular mouth is provided. Some examples, at 

 least, of the Wide-mouthed Lamprey, develop a throat pouch, as illustrated. 



