Analytical Synopsis of the Order of Squali. 395 



Rhinodontoidc'e. 

 Lamnoidoe. 



A. First dorsal entirely in advance of the pectorals ; 



rarely obsolete. 

 . B. Anal fin present. 

 C. Dorsal fins two. 

 a. Caudal lunate, very abruptly bent up- 

 wards ; tail keeled on each ^ide. 



Branchial aperture behind above pec- 

 toral. 

 Branchial apertures entirely before pec- 

 torals. 

 aa. Caudal moderately bent upwards, notched 

 near end, and with basal lobe small or 

 rudimentary ; tail not keeled. 

 D. Dorsals unarmed. Head normally de- 

 pressed. 

 U. Branchial apertures entirely before 



pectorals. 

 JEU. Branchial aperture behind above 

 pectoral. 

 a. Caudal exceedingly long. Eyes without 



nictitating membranes. 

 aa. Caudal moderately elongated. Eyes 

 with nictitating membranes. 

 Head laterally produced. 

 Head normally formed. 

 DD. Dorsals respectively armed in front 

 with a spine. Head high. 

 CC. Dorsal fin single; first obsolete. 

 BB. Anal fin absent. 



a. Snout normally formed. 

 Dorsals respectively spinigerous at front. 

 Dorsals unarmed. 



b. Snout prolonged like a saw. 

 AA. First dorsal above or behind the ventrals. 



B. Anal fin absent. 

 BB. Anal fin present. 



a. Caudal bent upwards ; with basal lobe. Ginglymostomatoidee. 



Odontaspidoidte. 



Alopecoidse. 



Cestraciontoidse. 

 Galeorhinoidse. 



Heterodontoida3. 

 Notidanoidse. 



Spinacoidse. 



Scymnoidre, 



Pristiophoroidse. 



Echinorhinoida3. 



