Evolution of (he Order Ileterosomata. 495 



Subfamily W. IhiOMBOSOLEiyjE. 



Dorsal fill extend iiifT forward on snout above nasal orj^an of 

 blind side ; pelvic fins forniod as in the Platoplirinae, tliat of 

 tli(i eyed side median, extendinjij forward to the urohyal, 

 f^upported by a cartihiijinous plato in advance of the cloithra; 

 that of the blind side small or sometimes absent. No pectoral 

 rudials, the rays inserted on the liyptM-eoracoid ; liypocoracoids 

 narrowed t'orward below. Vertebral column formed as in the 

 Pleuronectinie, the priccaudal parapophyses not united. 

 Mnuth asymmetrical ; jaws of the blind side strongly curved, 

 those of the ey»'d side toothless. 



Genera: — lihomhosoha^ Ammotrefis, and PeJtorhamphus 

 from Southern Australia ami New Zealand, with Uncoplerus 

 from Pata<^onia. 



I have examined the skeleton in lihombosolea (vcrtebraj 

 10-1-21) and I'eltorhamphus (9 + 27). 



Division 2. Soljeifo rmes. 



Mouth small, terminal, subterminal, or inferior, the lower 

 jaw never prominent ; j iws of the blind side toothed, stronj^ly 

 curved, the convexity of the lower fitting the concavity of the 

 upper ; jaws of the eyed side not or but feebly tootlied; praj- 

 opereular margin not free. Nasal organs symmetrical in 

 position; olfactory laminae arranged transversely to or 

 radiating from a central rachis. Optic chiasma dimorphic, 

 the right or the left nerve dorsal without reference to dex- 

 trality or sinistrality. No post-cleithruin ; no pectoral 

 radials, the rays inserted on the hypercoracoid ; liypocoracoid 

 reduced ; pelvic tins supported by the pelvic bones, which 

 are dependent from the lower extremities of the cleithra, 

 which do not reach the ventral [>rotile ; prsecaudal para- 

 pophyses united or connected by a bridge to form closed 

 hiemal arches ; no ribs. 



Family 1. Soleidae. 



Dextral. Caudal tin separate or not ; pectorals often 

 present ; both pelvic fins usually developed, but that of the 

 blind side sometimes vestigial or absent, that of the eyed side 

 sometimes median, with extended base. Vertebrte 28-57 

 (0-lO+19-4«). 



Principal genera : — Solea^ Synaptxira, ^sopia, Achirus, 

 I'urilachirus, lAachirus, GtjmnacliirHSj Api'oni'c/i(/ti/s, nujsfly 



