THE CHISMOPNEA (CHIMAEROIDS). 
The classification of this group of the fishes with cartilaginous fins and 
the reasons for the same are indicated in the synopses given below. 
CHONDROPTERYGH. 
Chondropterygit (part) LinNe, 1735, Systema, ed. 1; 1756, Syst., ed. 9, p. 41; Arrepr, 1738, Syn. p. 89, 
Gen. p. 64; Gmetrn, 1789, Linn. Syst., 1, p. 1483. 
Aquatic fish-like vertebrates in which the skeleton is cartilaginous and the 
skull without sutures; the heart has a conus anteriosus with three to four rows 
of valves; the brain has an optic chiasma; the intestine has a spiral fold; the 
teeth resemble the dermal armature and are not implanted in the cartilages of 
the jaws; the scales are placoid, and the vertical and the paired fins are mostly 
of horn-like tissue supported by cartilaginous radials; the eggs are large and 
fertilized internally, the male being provided with intromittent organs, claspers, 
attached behind the pelvis and the ventral fins; the embryo has deciduous gills. 
Gill openings 5-7; gills 5-7; notochord more or less segmented 
Dorsal fins rigid, not erectile 
Teeth numerous; rostralia fused with the cranium, not articulated 
Upper jaws not fused with the skull 
Male without frontal and prepelvice tenacula  . Plagiostomia 
Gill openings one on each side; gills 4; notochord unsegmented 
Dorsal fin and spine erectile 
Teeth six, plate-lke; rostralia three, articulated to the cranium 
Upper jaws and palatal cartilages fused with the skull 
Male with frontal and prepelvic tenacula . Chismopnea 
CHISMOPNEA. 
Chismopnea RAFINESQUE, 1815, Analyse de la Nature, p. 92. 
Holocephala Miuurr, 1834-1835, Vergl. Anat. Myx., 1, p. 10. 
Upper jaws and other palatal cartilages fused with the skull; rostral carti- 
lages three, articulated to the skull. One gill opening; four gill clefts; four 
