XXII1 OPISTHOMI——PEDICULATI Ff Mah 
two genera: Jastacembelus and Rhynchobdella. The largest 
species reach a length of three feet. Little is known of their 
habits. Of the Indian Rhynchobdella aculeata, Day says it 
conceals itself in the mud and becomes drowned in water if 
unable to reach the surface, as it apparently requires to respire 
air directly. 
Fic. 433.—Mastacembelus maculatus. x 
is 
Sub-Order 12. Pediculati. 
Air-bladder without open duct. Opercle large, hidden under 
the skin; supraoccipital in contact with the frontals, separating 
the parietals. Pectoral arch suspended from the skull; no 
mesocoracoid. No ribs, no epipleurals. Ventral fins jugular. 
Gill-opening reduced to a foramen situated in or near the axil, 
more or less posterior to the base of the pectoral. Body naked 
or covered with spines or bony tubercles. 
A small, natural group, connected with the Acanthopterygii 
Jugulares through the Batrachidae, in which the elongate pterygials 
of the pectoral fin foreshadow the kind of arm (“pseudobrachium ”’) 
which is more or less characteristic of these highly aberrant Fishes. 
As in ‘the Batrachidae, the post-temporal is flat and ankylosed to 
the cranium, and the suprascapula is much elongated. The ptery- 
gials, two or three in number, are separated from the small scapula 
and coracoid by a broad ligament, the arm-like pectorals being 
more or less distinctly geniculated and inserted far back behind 
the cranium. The head is large, the basis cranii simple. The 
gills are reduced to 2, 24, or 3. The spinous dorsal, if present, 
consists of a few rays, which may be modified into tentacles 
inserted on the head. Vertebrae 17 to 31. 
