139 



visible. For form and situation of pectorals and of the eyes 

 and for the transformation of lastnamed as well as for the 

 reduction of the anal papilla, see the figures. Length 20 mm. 

 Habitat: Near Salomakie (Dammar island), (surface plank- 

 ton)!; Banda sea (750 m.) ! 



Order MYCTOPHOIDEA >). 



Phystome. Scaly or naked. Lateral line present or absent. 

 Skull with a supraoccipital generally in contact with the 

 frontals, sometimes covered by the parietals. Maxillary excluded 

 from the gape of the mouth by the intermaxillary. Opercles 

 well developed, or their bones reduced. Anterior vertebrae not 

 coossified, forming no Weberian ossicles. Pectoral arch attached 

 to the skull by a forked posttemporal, no mesocoracoid. Fins 

 without true spines. Ventrals abdominal, by exception thoracic. 

 An adipose fin is typically present. Gillopenings very wide, 

 free from isthmus. Luminous organs .may be present. 



Artificial key to the genera. 



A. Luminous organs present. 



I. A pair of phosphorescent organs on the head, 

 covered by the thin frontal bones. No eyes. No 



luminous organs on body Ipnops p. 179. 



II. Luminous organs in rows on body. Eyes present. 



a. Height n or more, 60 scales in lateral line, 



opercular bones reduced Scopelosaurus p. 175. 



b. Height less than 6, 45 scales or less in lateral 

 line, opercular bones well developed. 



1. Origin of anal below end of dorsal. Lumi- 

 nous organs partly in groups . . Myctophum p. 151. 



2. Anal far distant from dorsal. A luminous 



organ below each of the ventral scales. . . Neoscopelus p. 173. 



B. Luminous organs absent. 



I. No scales. 



a. Origin of ventrals behind dorsal. Eye teles- 

 copic. D. 7 Dissoma p. 181. 



i) Having to treat only indo-australian forms, we unite under the name Myc- 

 tophoidea those fishes, which are generally arranged under the Iniomi, about 

 the validity of which large group there is no concordance among ichthyologists. 



