17^ FLATFISHES (HETEROSOMAIA) 



li. liyt'S separated by a more or less coiKa\i' sjiacc (except in very 

 young), which is usually broad in the mature male ; male 

 generally with one or more rostral spines. 

 * Less than 65 scales in lateral line ; gill-opening extending to 

 lateral line, or ending a short distance above pectoral fin, 

 in which case scaling of head and body is continuous below- 

 lateral line. 

 t Scales of ocular side rather feebly ctenoid ; maxillary 2i to 



3i in head ..... 25. ENtivrRosopoN. 



tt Scales of ocular side strongly ctenoid ; ma.xillary 3I to 



nearly 4 in head .... 2O. Crossorhombus. 



** More than 74 scales in lateral line ; upper angle of gill-opening 



a short distance above pectoral fin or close to lateral line ; 



membrane joining operculum to pectoral arch scaleless 



or partly scaled. 



t Eyes generally separated by a broad interspace (at least 



in male), the lower well in advance of the upper ; male 



nearly always with rostral and orbital spines ; teeth 



in jaws in two or more series (at least anteriorly)' : 



membrane joining operculum to pectoral arch scaleless 



27. BOTHfS. 



tt Eyes separated by a narrow or moderately wide space in 

 both sexes, the lower only a little in advance of the upper ; 

 male without distinct rostral or orbital spines ; teeth 

 uniserial in both jaws , membrane joining operculum 

 to pectoral arch partly scaled . . 28. Parabothus. 



b. Lateral line equally developed on both sides of body ; interorbital 

 region narrow, concave, similar in both se.xes ; scales small 



29. GRAMMATOBOTHrs. 



2. No pectoral fins. 



a. Scales small, ctenoid, the spinulcs directed horizontally ; body 



normal ....... .30. Mancopsetta. 



i. Scales very small, ctenoid, the spinules directed vertically, giving 

 the skin a pilose appearance ; body with a thick, muscular 

 central portion, continued abo\'e and below as a thin, semi- 

 transparent region . . . . -31 ACHIROPSHTTA. 



!■. -Mouth very large, iTia.x!llar\' more than J head ; lower jaw very promi- 

 nent : body elongate. 



1. Mandibular membranes not forming a pouch ; only the tip of lower 



jaw projecting ...... 32. Chascanopsktta. 



2. Mandibular membranes forming a gular pouch : about ^ of length of 



lower jaw projecting ..... 33, Pelecanichthys. 



11 Dentition nearly entirely confined to blind side of jaws; mouth small, 



protractile, maxillary 38 to 4? in head ..... 34. L.^OPs. 



The subdivision into genera of the subfamily Bothina?, and particularly of those 

 related to Ayiioglossxs, Engvpinsopun, Bothus, etc., presents some difficulty.- The 

 form of the gill-openings, although a useful character, proves to be of less imjiortance 

 than it was believed to be, and the form of the interorbital region, dentition, and 

 the scaling are all very' variable features. The arrangement of the olfactory lamina" 

 in the nasal organs provides a character which is somewhat more reliable, but this 

 requires further investigation with well-preserved material.^ Weber and Beaufort,'' 

 working on Indo-Australian Heterosomata only, would unite the genera Anmglossus, 



p. 4().s. 



