6 Mr. C. T. Regan on the Anatomy and 



vomerine teeth sometimes absent and anterior supramaxillarj 

 wanting; a single large supramaxillarj, superiorly sending 

 forward a pointed process ; subocular shelf a small or slender 

 process of the second suborbital ; nasals very large, united 

 by suture throughout their length, covering the ethmoid and 

 the prsemaxillary processes. Frontals, parietals, and supra- 

 occipital, with their ridges and crests, arranged much as in 

 the Berycidffi. Alisphenoids separate, bridged by the orbito- 

 sphenoid. Hypocora'coids narrowed forward below, not 

 reaching the ventral profile, not embracing the pelvic bones, 

 which are firmly attached to the cleithra above the symphysis. 

 26 vertebrae ; no upturned centra, and the anterior uroneural 

 ankylosed with the last centrum. Abdomen with a median 

 series of ridged or serrated scales. 



Recent genera are TracMchthys^ Shaw, Iloplostethua, Cuv. 

 &Ya\., Paratrackichfhys, Waite, and Gephyroberyx, Houleng. 

 The Cretaceous Aipickthys, Steind., and Acrogaster, Agass., 

 may be provisionally referred to this family. Sphenocephalus, 

 Agass., shows some resemblance to Trachichthys, but does 

 not seem to have the abdominal series of ridged scales. 



Family 6. Monocentridae. 



Differs from the preceding only in the large, bony, rigidly 

 united scales, the absence of the first four ribs, and the reduc- 

 tion of the pelvic fin to a spine and 3 soft rays. The trunk- 

 muscles are inserted only on the posterior surface of the 

 skull, and on the upper surface the occipital and parietal 

 crests are converted into ridges bordering mucous channels. 



One genus, Monocentris, Bl. Schu. 



Family 7. Anomalopidae. 



Differs from the Trachichthyidge in the absence of mucous 

 channels on the head and in the presence of a peculiar evertible 

 subocular luminous organ. 



There is a single example of Anomalops hatoptron, Bleek., 

 in the British Museum, and I have ascertained that the nasal 

 bones, the orbitosphenoid, and the supramaxillary are as in 

 the Trachichthyid^. There is a median abdominal series of 

 ridged scales and the caudal fin has 17 branched rays. In 

 this specimen the right pelvic fin is absent and the left has 

 only 4 rays ; these fins are said to be normally 6-rayed, but 

 authors disagree as to whether the outer ray is spinous or 

 articulated. Protohlepharon palpebratus, Bodd., which has 

 been figured by Max Weber {' feiboga ' Exped. p. 109, 1902) 



