Jordan and Evennaiiii. — Fishes of Morth America. 35 



.//■. N;is:il ll;i|, witli an acute- I. .!.,•. 



/(. Sii.iut iiiit very slicjit, its leiistli I'fom iiidutli not notably less 

 than widtli ofniuuth. (.'olur yellow isli limwn. 



ACUONOTUS, 42. 



/»/(. Snout very sliort and blunt, its length from mouth liut% widtli 



of mouth. PKiiEzr, 43. 



ee. Distance fioni end of base of first dorsal, to vontrals fri'fater than len};th 



of fust dorsal ; pnout moderate. UEMotis 44. 



dd. Length of snout from mouth greater than width of moutli; first dorsal small. 



iiK.NLi:i.45. 

 C.VRCHAniiiNi's: 



hh. Upper teeth triangular, Ruberect, scarcely notched on the outer margin ; lower teeth 



similar but much narrower. 



I. Snout moderate, its lengtli from mouth about equal to width of mouth. 



j. rectorals not falcate ; fins not conspicuously darker at tijjs. .Mlaiitic. 



MI1.I!KRTI, 40. 



jy'. Pectorals somewhat falcate ; second dorsal rather smaller than anal ; tins 

 scarcely dusky at tip. Tacific. lamiella, 47. 



a. Snout very short, its length from mouth less than widtli of mouth. 



A-. Pectoral long and falcate, reaching to posterior part of base of dor.sal. At- 

 lantic. 

 \. Anterior margin of first dorsal convex, the height of the fin about ecpial 

 to ilepth of body. lamia, 48. 



kk. Pector.al fin moderate, scarcely falcate, not reaching to end of base of dor- 

 sal. 

 r». Second dorsal not larger than anal; length of snout from mouth IJ^ 

 times in breadth of mouth; upper teeth very broad. Atlantic. 



PLATYODON, 49. 



mm. Second dorsal larger than anal. 



H. Length of snout from mouth but y, breadth of month; upper teetli 



not very broad; head very broad above. Pacific. fronto, 50. 



nn. Length of snout from mouth more than J<^ breadth of mouth; 



fresh waters. nicakaguensis, 51. 



IsoooMPUODoN, (i<TO!, equal; ydfic^o?, nail; 6<?ov5, tooth): 



ail. Teeth slightly serrated, similar in form in the two jaws, narrow, claviforra, constricted at 



base; snout rather sharp. 



0. Snout moderate, its length from mouth not greater than the breadth of mouth; teeth 



moderate, about .30 in each jaw; fins edged with black. 



|). Baseof anal a little longer tlian that of second dorsal; pectoral reaching end of base 



of first dorsal. /i;tiiai,orus, 52, 



j)^. Base of anal equal to that of second dorsal; pectoral reaching i)ast base of first 



dorsal. limi!atiis, 53. 



oi>. Snout very long and narrow, its length from mouth twice distance between nostrils; 



teeth small, about 48 in each jaw. oxyriiynchus, 54, 



Subgenus PLATYPODON, Gill. 



35). (ARCHAUHINrS OBSC'IKIS, (Lo Sueur). 



(DusivY Shark,) 



Head rather jioiuted, llatteiied above and below ; fust dorsal rather 



large ; second dorsal smaller than the anal, and considerably produced 



behind; pectorals very largo, falciform, extending beyond the end of the 



dorsal, their outer margin 4 times the inner. Dark clear blue above, 



white below. A large shark, reaching a length of 9 or 10 feet, inhabiting 



the Middle Atlantic and fieqnently taken on our coast. {ohscuruK, dusky.) 



Sijimhis (ihscimts, Le Sueur, .Toiir, Ac, Nat, Sci. Phila., 1S18, 1, 223, New York, 

 Vnrrhitr'um olts^cnniK, GfNTliER, Cat,, Vlll, 300, HmO. 

 GmloiihiniiK (iliyi-in-im, JoRliAN & GlI.iiERT, Synopsis, 22,1883. . 

 Carrlutrin^ /(dcipiunis, LowE, Proc. Zoil. Soc. Loud., 18.3!i, 00, Madeira. 

 Prionodon obvelatus, Valenciennes, Poiss, lies Canaries, 103, 1836, Canaries. 



