THE CIIISMOPNEA (CHIMAEK'OIDS). 



The classification of this grouj) of tlic fislics with cartihiginous fins and 

 the reasons for the same are indicated in tlie synopses given below. 



( "llONDKUl'TEKVlill. 



Chonilru/Hcri/ijii (part) LiNNii, 17o.'), Sy.sti'ina, t'd. 1; IToO, .Syst., eil. ',), ]>. 11; AuTiiDi, 173S, Syri. p. S9, 

 Gen. p. 64; Gmelin, 1789, Linn. .Syst., 1, p. 14S3. 



.Vquatic fish-like vertehrates in wliii'h the ski^lcton is cartilaginous and the 

 skull without sutures; the heart has a coiius antcriosus with three to four r(nvs 

 of valves; the hrain 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 phicoid, and the vertical and the jiaired 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, clasjiers, 

 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 withnut frontal and prepelvic tenacula . PUujiodoinia 

 Gill openings one on each side; gills 4; notochord unsegmented 

 Dorsal fin and spine erectile 



Teeth si.x, plate-like; rostralia three, articulated to the cranium 

 Upper jaws and palatal cartilages fused with the skull 



Male with frontal and prei)elvic tenacula . ('Iiiainopiica 



Chismopne.\. 



Chismoimca Rafinesque, 1815, .Analyse dc la Nature, p. '.IJ. 

 Holnc(i>ltal<i MuLLEH, 1834-1835, VitkI. -\nat. Myx., 1, ]>. 10. 



Upper jaws and other palatal cartilages fused with the skull: rostral carti- 

 lages three, articulated to the skull. One gill o]iening; four gill clefts; four 



