KISllKS — WAITK. 67 



/;//////// MONOCENTRID^. 



M N O C ]i: N T Jl 1 S, Schneider. 



MONOCENTRIS GLORIA-MARLS, De Vis. 



Knkjut Fish. 



(Plate viii., ligs. 1 and _!.) 



Cleidopus (jloria-marit<, De Vis, Pruc. Liiiii. !Suc. N.iS.W., vii., 



1882, p. 368. 

 Monocentris gloria-niaris, Ogil., Pruc. Linn. Soc. N.S.W., xxiv., 



1899, p. 159. 



Stations 5, 10, 28, 29. 



At each of the above mentioned stations we o))tained an 

 example of this fish. It was taken noi^thward of Port Jackson at 

 depths varying from 17 to 84 fathoms. In life the mandibulary 

 luminous organs were of bright crimson colour with a brilliant 

 white line along the upper edge : in spirits the discs of two 

 examples have turned brick-red, in the other two a pearly-grey ; 

 all four exhibit the white line. These discs are situated externally 

 one on each side of the mandible, are fully exf)osed when the 

 mouth is open, but completely concealed by the maxillary when 

 closed. The organ is subreniform in sha'pe and measures 6 mm. 

 in length and 3 mm. in depth in examples 200 mm. in length. 



The dorsal spines are normall}^ six in number, but one, two, or 

 even three of the posterior ones may be undeveloped and repre- 

 sented only by the rugose portion found at the base of each spine. 

 They are markedly heterocanth in character and are subject to 

 variation as follows. While in some examples the first spine is 

 directed to the right, the second to the left, and so on throughout 

 the series, in others the condition is reversed, the first spine 

 tending to the left, the second to the right, and so on alternately; 

 in other words, we might say they are either right or left handed. 

 All the spines are joined to each other by a low but very strong 

 membi'ane. 



The ventral spines, when erected, have an almost horizontal 

 aspect, and can be securely locked at right angles to the body ; 

 the mechanism by which this locking is effected has been fully 

 described in M. japonicus by Thilo in his admirable treatise.* 

 These spines are of enormous size and strength, and in a specimen 

 measuring 190 mm. in total length the pair when erected compass 

 130 mm. from tip to tip. 



* Otto Thilo— Morph, Jahrb., xxiv., 1896, p. 336. 



