AET. 10 



NOTES ON MYCTOPHINE FISHES PARR 



29 



p. 115), together with D. agassizi Gilbert 1908/° but not in a separate 

 Division I. 



D. urolamipus is distinct from D. du7iierili Bleeker, in which 

 species it was tentatively included by Weber and Beaufort, 1913,^' 

 in the absence of a suborbital organ, in the elevation of the first AO 

 anterior and in having the VLO situated close to the lateral line, 

 not at a considerable distance below it. The latter feature also dis- 

 tinguishes D. urolarti'pus from D. agasslzi Gilbert, with which species 

 it is otherwise very closely related. These differences have been 

 further made out in the following supplementary key to the species 

 of the genus Diaphus, which have only one small antorbital organ on 

 each side, entirely above the nostril (Division II A in the previ- 

 ously rendered key. Parr 1928, p. 115). 



I. Upper SAO and Pol close to or in contact with the lateral line. 



A. VLO in contact with or very close to the lateral line. First AO anterior 



elevated. 



D. urolampus Gilbert and Cramer. 



B. VLO well below the lateral line. 



D. dumerili Bleeker. 

 D. agassizi Gilbert. 

 (See Parr 1928, p. 115.) 



II. Upper 8A0 and Pol well below the lateral line. 



D. gemellari Cocco. 

 D. doflelni Zugmayer. 

 D. nipponensis Gilbert. 

 (See Parr 1928, pp. 115-116.) 



Measurements of Diaphus Urolampus Oilhert and Cramer, 1S97. Type specimens 



No. 1,1109 V.S.N.M. 



[In per cent of total length without caudal fin) 



Total length without caudal fin in mm 



Length of head 



Greatest height 



Length of lower jaw 



Diameter of eye 



Distance snout to D 



Distance snout to V 



Distance snout to A 



75 



30 

 20 

 23 



8.0 

 42 

 44 

 65 



Upper antorbital very small, but distinct and normally developed. 

 No lower antorbital, no supra or suborbital organs. PLO much 

 closer to the lateral line than to the base of pectoral fin. PVO in 

 a straight series with the anterior PO. Fourth PO elevated to some- 



2«Z). dumerili Bleeker, 1856, has for practical purposes been included both in this 

 division and in Division IV, where it properly belongs, as the suborbital organ, though 

 always present, is often difficult to make out on account of its minuteness. 



2^ This view has been accepted by Fowler, 1928 (p. 68). 



