FISHES OF NEW YORK 



37 



MEASUREMENTS 



Width of nostril 



Distance between nostrils 



Nostril to front of mouth 



Length of mouth opening ,_ ^ 



Width of mouth, including labial folds 



Length of labial fold 



Labial fold to first gill opening 



Snout to first dorsal 



First dorsal base 



Middle of dorsal base to top of fin 



Length of posterior margin of dorsal 



From first to second dorsal 



Length of second dorsal base 



Middle of second dorsal base to top of fin 



Posterior margin of second dorsal 



Second dorsal to caudal pit 



Caudal from pit 



Lower caudal lobe 



Terminal caudal lobe 



Snout to pectoral, obliquely 



Length of pectoral 



Lower margin of pectoral 



Extended pectoral not quite reaching to perpendicular 



through front of dorsal. 

 Ventral origin slightly behind end of first dorsal base 



Length of ventral 



Inner margin of ventral 



Vent to tip of clasper 



End of ventral base to origin of anal 



Anal base 



Hind margin of anal 



Depth of anal 



Anal base to origin of lower caudal lobe 



Feet 



Inches 



% 



1/2 



2% 

 4 

 1 



3% 

 16 



3 



5 



2% 



21/2 



m 

 3 

 12 



9% 

 3 

 loya 



5 

 2^A 



3y8 



1% 



m 



3% 



3 



1 



2 



1% 



Family laniniidae 



Mackerel Sharks 



Genus isurus Bafincsque 

 Body fusiform, stout; mouth wide, witli long, sharp edged, 

 lanceolate, entire teeth having no basal cusps ; spiracles minute 

 or absent; gill openings wide, all in advance of pectorals, lateral, 

 not extending under the throat; first dorsal large, not far be- 

 hind origin of pectoral; second dorsal and anal very small; peo- 



