72 



BULLETIN OF THE 



CHONDRICHTHYOIDEA. 



With the nasal canals in front of the 

 nostrils ; 

 cranial meeting the aural 



HOLOCEPHALA.. 



canals sulcate Chimcera monstrosa. 

 canals tubular Callorhynchus antarc- 

 ticus. 

 With the nasal behind the nostrils ; 

 cranial not meeting the aural 



Selachia. 

 without pleural canals Galei. 



with pleural canals Batoidei. 



Galei. 



Oral not connected with angular ; 

 median longitudinal ; 

 cranial curves abrupt, deep 



Scoltodon terrce novce. 

 cranial curves shallow ; 

 an upward anal curve ; 

 jugular reaching toward upper 

 edge of gill opening; 

 anal curve prominent 



Mustelus canis. 

 jugular reaching toward middle 

 of gill opening ; 

 anal curve low 



Triads semifasdatus. 

 jugular curved downward 



Scylliorhinus caniculus. 

 anal curve indistinct; 

 nasals not meeting 



Acanthias americanns. 

 suborbitals and subrostrals on 

 top of snout Rhina squatina. 

 median transverse ; 



anal curve absent Prionodon milbertii. 

 Oral connected with angular , 

 divided at the symphysis ; 

 cranials folded over themselves 



Cestracion tiburo. 

 cranials not folded ; 



suborbital and angular meeting; 

 median transverse ; 

 jugular passing below gill 

 opening Alopias vulpes. 



median longitudinal ; 



jugular passing toward middle 



of gill opening 



Odontaspis americanns. 



jugular short, passing toward 



upper edge of gill opening 



Heterodontus philippii. 



spiraculars and gulars present 



Chlamydoselachus anguineus. 



not divided at the symphysis 



Ginglymostoma cirratum. 



suborbital and subrostral meeting 



Isurus punctatus. 

 Oral absent ; 



aural divided ; 



nasals not meeting 



Heptabranchias maculatus. 

 aural entire ; 



nasals not meeting 



Pristiophorus cirratus. 



nasals meeting Somniostis carcharias. 



Batoidei. 



Subpleurals in front of gill openings ; 

 pleural descending on edge of disk 



Pristis perfinatus. 

 pleural passing through disk ; 

 sternal divided ; 

 rostrals and prenasals long 



Rhinobatus planiceps. 

 sternal entire ; 

 rostrals and prenasals short 



Syrrhina brevirostris. 

 Subpleural and other ventral canals ab- 

 sent ; 

 tubules very short Narcine brasiliensis 

 tubules medium ; 



aural tubules very short 



Torpedo marmorata. 

 tubules long ; 

 aural tubules long 



Torpedo cali/ornica. 



Subpleurals at side of gill openings ; 



tuDules simple ; a long post-scapular 



tubule ; 



orbito-nasal at right angles with 



pleural Uraptera ayassizii. 



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