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



The new genus Parasudis^ here established for Chloro- 

 2^Jithalmus trucidentus, Goode & Bean, differs from Chloro' 

 jyhtkalmus in thai the snout is produced so that tlie maxillary- 

 does not reach the eye, whilst the body is more compressed 

 and the vent is placed further back. It is clearly annectant 

 between Chlorophthalmus and Paralepis and invalidates the 

 claim of the latter to rank as tlie type of a separate family. 

 I find that in Paralepis and Sudis the mouth structure is very- 

 similar to that of Chlorophthalmus ; the maxillary is more 

 slender and more adherent to the prsemaxillary, but it is 

 somewhat dilated distally and bears a long supramaxillary 

 just as in Chlorophthalmus. 



Family 4. Myctophidae. 



Closely related to the Sudidse, from which they differ 

 especially in that (1) a median keel is present on the ethmoid, 

 and (2) the parasphenoid extends upwards to the frontals 

 between the lateral ethmoids. As in the Sudidge, the vomerine 

 teeth, when present, form two well-separated patches. Tlie 

 body is oblong, compressed ; the head is compressed, with 

 the eyes lateral and the mouth terminal. In the more primi- 

 tive genera the mouth is formed as in Chlorophthalmus ^ with 

 the maxillary strongly expanded behind and bearing a supra- 

 maxillary; but in the more specialized forms thesuspensorium 

 is directed obliquely backwards and the slender maxillary is 

 adherent to the prsemaxillary, almost as in the Synodontidse. 

 In Scopelengys, Alcock, there are no photophores. Neo- 

 scopelus, Johnson, has a luminous spot on each scale of the 

 lower part of the body, whilst in Scopelopsis, Brauer, every 

 scale bears a spot. In Myctophum and its allies the photo- 

 phores are arranged in definite groups and series. This is 

 apparently the only family of tlie order in which an air- 

 bladder may sometimes be present. 



JSeoscopelus is a very generalized Myctophid ; the bones 

 are thin, and the skull is less expanded behind the orbits and 

 has the sphenotic process less prominent than in Aulopus. 

 The parietals are separated by the supraoccipital, the posterior 

 temporal fossEe are not roofed, there is no orbitosphenoid, and 

 the parasphenoid is slender. As already indicated, the latter 

 bone meets the frontals just behind their junction with the 



C. Lower part of pectoral of 12 to 14 rays. 

 Outermost pelvic ray not or scarcely produced . . longifiUs, Giinth. 

 Outermost pelvic ray moderately produced .... { Si-urn' Alcock. 

 Outermost pelvic ray considerably produced .... ventralis, Garm. 



