200 MR. C. TATE REGAN ON THE 



in the young, whilst the fins have a few cross-bars, which later on break up into spots, 

 and these spots, like those on the head and body, seem to continually increase in 

 number with increased size of the fish. 



Measurements. 



In descriptions of species the total length means the distance from the tip of the 

 snout to the base of the caudal fin ; but where the total length (in millimetres) of the 

 largest specimen described is given, the length of the middle rays of the caudal fin is 

 included. In the armoured forms the length of the head is measured to the posterior 

 margin of the temporal plate, but in the naked-bodied Argiinse to the edge of the bony 

 operculum. In some cases it has been found useful to indicate the size of the mouth 

 by giving the proportion of the length of the mandibular ramus — i. e. of that box-like 

 tooth-bearing portion of the mandible which borders the mouth — to the interorbital 

 width. In counting the scutes, that one which is posterior to the clavicle is reckoned 

 as the first, whilst the movable plates covering the bases of the caudal rays are not 

 included. The length of the base of the dorsal fin is measured from the base of the 

 first developed ray to the base of the last, the membrane behind the last ray being 

 excluded. The sign f prefixed to the name of a species indicates that the author 

 has not examined actual specimens, but has based his description on the published 

 accounts. 



Family LOEICAEIID^. 



Ostariophysi with parietals and supraoccipital united to form a single parieto-occipital 

 bone, without suboperculum, symplectic, or metapterygoid ; palatine a,rticulating 

 posteriorly with the prefrontal and anteriorly with the small rod-like maxillary, which 

 bears a barbel ; prsemaxillaries not protractile, forming the entire upper border of the 

 mouth. Caudal vertebra? compressed, with expanded and compressed neural and 

 haemal spines ; prsecaudal vertebrae without parapophyses ; coalesced anterior vertebrae 

 with outgrowths on each side which are suturally united to the cranium, forming, with 

 the exoccipitals, two capsules enclosing the two halves of the reduced air-bladder; 

 the last (fifth) bearing a pair of strong ribs, articulating with the first free vertebrse by 

 a hinge which permits only of vertical movement ; ribs of the free prsecaudal vertebra?, 

 if present, sessile. Nostrils close together, a flap between them ; mouth inferior, with 

 expanded and reflected lips ; jaws with teeth ; palate toothless ; lower and fourth 

 upper pharyngeals with or without teeth ; four gills, a slit behind the fourth ; pseudo- 

 branchiae present or absent; gill-membranes broadly joined to the isthmus; four 

 branchiostegals. Dorsal fin usually above the praecaudal portion of the vertebral 

 column ; adipose fin often present ; anal fin short ; ventrals below or in front of the 

 dorsal ; anterior rays of dorsal, anal, pectoral and ventral, and outer rays of caudal 

 simple, often spinous. 



