352 



Part III. — Eighteenth Annual Report. 



Families. Sub-families. 



(Hippoglossince. 

 Pleuronectince. 

 Hippoglosso-rhom bince. 

 Rhombhw'. 



{ Soleinw. 

 - < Achirince. 

 { Cynoglossiii'i'. 

 Solei-'pleuronectiwM. 

 Incertce sedis ? 



Pleuronectidm 



Sole idee 



Sub-Fam. Hippoglossinaj. 



(1) Preopeixmlar margin distinct, not hidden by the skin and 

 scales of the head. 



(2) Olfactory laminse arranged longitudinally with median 



rachis. 



(3) Ventral fins placed symmetrically about ventral line of 

 body, the pubic bones being wholly behind the base of 

 the clavicles and connected thereto by a ligament. 



(4) Nasal organ of blind side lies anterior to the anterior 



extremity of the dorsal fin on the ridge of the head. 



(5) Mouth nearly symmetrical, the dentition nearly equally 



developed on both sides ; gape large ; lower jaw most 

 prominent. 



(6) Eyes on right side, large, 



This sub-family, restricted by the above characters, includes the 

 following genera : — 



Species Examined. 



Gemis. 



Distribution. 



A. stomias 



P. hipjwglossoides . 

 H. vulgaris . 



(?) 

 (?) 



I), elassodon . . \ 

 D. platessoides . ] 

 P. melanost ictus . 



(?) 



(?) 

 (?) 



Atheresthes, Jordan and 



Gilbert. 

 Platysomatichthys, Bl. 

 Hippoglossus, Fl. 

 Lyopsetta, Jordan & Goss. \ 

 Eopsetta, „ / 



Drepanopsetta, Gill. 



Psettichthys, Girard. 

 Verasper, Jordan & Gilbert. 

 Hippoglossina,Steindacliner 



Lioglossina, Gilbert. 

 Xystrenrys, Jordan and 

 Gilbert. 



Bering Sea to San Francisco. 



Arctic parts of the Atlantic. 

 North Atlantic and North Pacific 



California and North Pacific. 



North Atlantic and North Pacific ( 



Pacific coasts of North America. 

 J apan. 



Pacific Coast — California to 



Mexico. 

 California 

 South California. 



The last three genera are placed as doubtful because they may belong 

 to the family of the Hippoglosso-rhombinse. They are said by Jordan to 

 be closely related to Paralichthys, and this, along with their southerly 

 distribution, their tendency to be either sinistral or dextral — a character- 

 istic of the Hippoglosso-rhombince — raises the doubt as to whether they 

 should be grouped with the Hippoglossinae or with the latter group. It 

 is possible, also, that Verasper should accompany the other three genera. 



This family includes Atheresthes and Platysomatichthys, which are 

 generally believed to be more closely related to the primitive ancestors 

 of the Heterosomata than any of the other species. The evidence on 

 which this is based rests almost entirely on the position of the left eye, 



