300 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



PARALICHTHYS 



Definition. — ^Mouth symmetrical, large, maxil- 

 laiy reaching a vertical through middle of eye 

 or more posteriorly, position of postei'ior extrem- 

 ity of maxillary depending largely on size of 

 fish. Ventrals symmetrically placed on both sides 

 of abdominal ridge, the fins from both sides sub- 

 equal in length and in -width of base. Pectoral 

 longer on eyed side, base snbequal on both sides, 

 none of the rays notably prolonged. Body sinis- 

 tral in most species, in 2 species varies with indi- 

 vidual fish being nearly as often dextral as 

 sinisti^al (another species is known from 1 dextral 

 specimen). Lateral line present on both sides; 

 with a well marked curve in front over pectoral 

 fill; with an anterior accessory branch more or 

 less developed, usually more or less disconnected 

 from main lateral line, extending forward and 

 more or less upward, generally not reaching dorsal 

 profile, sometimes reaching there as an individual 

 variation. (The accessory branch of the lateral 

 line is somewhat better developed in calif ormcus^ 

 aestua'rius, adspersvis, and woolmani, where it 

 sometimes reaches the dorsal profile, especially in 

 the larger specimens; but is present to a greater 

 or lesser extent in all the species, is highly variable 

 with the individual in its extent, and is evidently 

 of no importance in distinguishing the species.) 

 Teeth in jaws in one row, similar on both sides; 

 the anterior teeth more or less enlarged, caninoid, 

 especially those of upper jaw, but no marked 

 fangs present ; no teeth on vomer or palatines. 

 Scales medium or small ; ctenoid on eyed side and 

 cycloid on blind side (in subgenus Paralichthys; 

 some ctenoid scales infrequently present on caudal 

 ]3eduncle of blind side in adspersus and calif oi'mi- 

 rus, while in aestuari/im the scales on eyed side 

 become cycloid in large specimens) ; or scales all 

 cycloid on both sides at all ages (in the subgenus 

 Ghaenofsetta). Accessory scales present, usually 

 beginning to develop in fish reaching a length of 

 75 to 155 mm., the first appearance of accessory 

 scales with respect to length differing with the 

 species and to a lesser extent vai*ying with indi- 

 vidual fish. Gill membranes united, free from 

 isthmus. Dorsal origin over or in front of anterior 

 margin of upper eye in mediinn-sized or large 



specimens, more or less behind anterior margin 

 of eye in j'oung fish, nearly over middle- of eye 

 in adults, also, of one species; anterior dorsal rays 

 not markedly j^rolonged. Rays of vertical fins 

 sim]i]e, except hindmost; posterior 1 to o rays 

 first becoming split in fish reaching a length of 

 40 to 60 mm., the number of branched rays and 

 the mnnbcr of dichotomous branchings increasing 

 with size ; total number of branched rays in large 

 fish 5 to 15, with the posterior 2 or 3 sometimes 

 branched dichotomously 3 times, except some- 

 times as an individual variation the ultimate ray 

 and less often also the jienultimate remaining 

 simple in large specimens as well. The inter- 

 orbital wider than a mere ridge, except in young 

 fish ; its width not differing notably with sex. Eye 

 medium or rather small, the eyeball usually 5 

 percent of standard length or less in large or 

 medium specimens. Gill rakers always consider- 

 ably longer than wide, pointed or narrowly 

 rounded at apex; few and more or less short and 

 broad, to many and quite long and slender. Ver- 

 tebrae 10 to ll-t-23 to 31, the number differing 

 interspecifically, and somewhat varying intra- 

 specifically with the individual (p. 299). Caudal 

 roimded in young fish, becoming more or less 

 biconcave in specimens over 100 or 200 mm., the 

 biconcave condition becoming more pronounced 

 with growth, the upper and lower angles becom- 

 ing more or less produced in large fish. (The size 

 at which the gi-adual changes occur and the rela- 

 tive development of the biconcave condition differs 

 somewhat with the species but the differences are 

 not sufficiently pronounced to be used in specific 

 distinction. ) Typical color pattern in 5 longitudi- 

 nal rows of spots, the most prominent spots oc- 

 cupying various positions within the typical 

 pattern depending on the species (p. 277). The 

 prepeduncular spot prominent in most species, 

 forming part of either the large or the small 

 triangle or both. 



Paralichthys is most nearly related to Hippo- 

 glossina and Pficmlorhomhiis as discussed under 

 those two genera (pp. 287 and 298) . It is divisible 

 into two subgenera, Paralichthys and Uhaenop- 

 setta. The following account of the genus in- 

 cludes all the known species except olivaceus 

 from the coasts of Japan and China. 



