220 "ENDEAVOUR" SCIENTIFIC RESULTS. 



of parallelism ; and finally, the ambicoloration and 

 reversal of certain examples of the genus Rhombosolea, 

 with the associated variations towards symmetry shown 

 by the pelvic fins. 



I take this opportunity of offering my thanks to the 

 late Allan R. McCulloch and the Director of the Aus- 

 tralian Museum for their kindness in entrusting me with 

 this investigation, and for providing me with an excellent 

 series of additional specimens, and notes and illustra- 

 tions of others concerning which I was in doubt; and to 

 Mr. E. R. Waite, for his assistance in providing me with 

 South Australian material, and for generously placing 

 in my hands the notes on this group which had been 

 already made by him. Finally, I have to thank Mr. C. 

 Tate Regan, F.R.S., for the valuable advice which he has 

 given me during the preparation of this report. 



The scheme of classification adopted is that published 

 by Mr. Regan in 1910. 2 



ARTIFICIAL KEY TO THE FAMILIES AXD SUBFAMILIES OF 

 HETEROSOMATA REPRESENTED IN AUSTRALIA. 



I. Dorsal fin not extending forward on the head, the anterior 

 rays spinous; each pelvic fin with a spine and five soft 



rays; eyes on the right or left side 1. PSETTODID. 



II. Dorsal fin extending forward on the head at least to above 

 eye, none of the rays spinous; pelvic fins without spine. 



A. Praeoperculum with a free margin, lower jaw generally 



prominent. 



1. Eyes on the left side, except in reversed examples. 



2. BOTHID.E 



a. Pelvic fins equal, short based .... 2a. Paralichthhia' 



b. Left pelvic fin median, with base much longer than 



that of right 2b. Bothinte 



2. Eyes on the right side, except in reversed examples. 



3. PLEURONECTID^ 



a. Mouth symmetrical, with the jaws and dentition 



nearly equally developed on both sides; anterior 

 rays of dorsal fin greatly prolonged. 3a. Samarincc 



b. Mouth usually asymmetrical, the dentition always 



more developed on the blind side; anterior dorsal 

 rays not greatly prolonged ... 3b. Rhombosoleintr 



B. Praeopercular margin not free, hidden by the skin and 



scales of the head; lower jaw never prominent. 



1. Eyes on the right side 4. SOLEIDJE 



2. Eyes on the left side 5. CYNOGLOSSID.B 



2 Ann. Mag. Nat. Hist., Ser. 8, VI, 1910, p. 484. 



