FISHES. MCCULLOCH. 163 



ALEPOSOMUS, ROULEINA, SQUAMILATERUS Alcock. 

 (Plate xliv, fig. 1.) 



Xenodermichthys sqiianiilatcnis Alcock, Ann. Mag. Nat. 

 Hist. (7) ii, 1898, p. 148 and Cat. Ind. Deep-sea 

 Fish. Investigator, 1899, p. 181. Id. Illustr. Zool. 

 Investigator, Fishes, 1899, pi. xxv, fig. 4. 



D.20; A.19; P.8; V.7; C.19. 



Head, from premaxillary syinphysis to end of 

 opercnlar lobe, 3-8 in the length to the base of the caudal 

 rays ; depth at the pectorals 5-9 in the same. Transparent 

 disc of the eye considerably smaller than the orbit, 4-0 

 in the head; bony orbit 3-3 in the same. Snout 1-6 in 

 the orbit. 



Body elongate, compressed. Profile forming a 

 convex curve upwards from the snout to the back; the 

 snout a little prominent. Interorbital space flat; its 

 bony portion is about half as wide as the eye but the 

 bones are so soft that they cannot be satisfactorily 

 measured. Nostrils large, close together; the anterior 

 circular, the posterior a pear-shaped opening. Eye 

 entirely within the anterior half of the head and close 

 to its upper profile. Preorbital very narrow and mem- 

 branaceous. Mouth large, oblique; the maxillary is 

 broad and rounded posteriorly, with a well developed 

 supramaxillary, and reaches backward almost to the 

 vertical of the posterior margin of the eye. Mandible 

 closing within the premaxillaries but with a very 

 prominent syinphysial angle. Preopercular angle partly 

 free, the rest of its margin covered by dermal membrane. 

 Opercles membranaceous, supported by stronger bony 

 ridges curving obliquely downward to an inframarginal 

 angle; a broad skinny border forms the margin of the 

 gill-opening. Gill-openings very wide, commencing high 

 above the pectoral and only a short distance below the 

 lateral line; they extend forward to below the eye and 

 the membranes are quite free from the isthmus. Four 

 gill-arches, with a slit behind the fourth ; pseudobranchise 

 present. About nineteen broad gill-rakers on the lower 

 limb of the first arch, of which those at the posterior 

 angle are about half as long as the orbit. Premaxillaries 

 with a single row of minute cardiform teeth which 

 extends backward onto the lower edge of the maxillary; 

 a similar row on each side of the mandible; palate 

 toothless. Tongue large and free. 



