352 NEW-YORK FAUNA. 



GENUS LAMNA. Cuvier. 



Snout pyramidal, with the nostrils under the base. Branchial apertures all in front of the 

 pectorals. Temporal orifices wanting. 



Obs. Some of the recent English systematic writers have added to these characters, the 

 following : " First dorsal in advance of the pectorals, and sides of the tail carinated." We 

 prefer the less restricted characters assigned to this genus by Cuvier. 



THE MACKEREL PORBEAGLE. 



LlMNA PDNCTATA. 



PLATE LXni. FIGS. 206 & 207. — (CABINET OF THE LYCEUM.) 



The Green-backed Shark, Squnius punctatus. Mitchill, Trans. Lit. and Phil. Soc. Vol. 1, p. 483. (Young.) 

 Lamna punctata, Mackerel Shark. Storee, Massachusetts Report, p. 185, pi. 3, fig. 2. 



Characteristics. Teeth in front long and sinuous ; behind, triangular, and all with smooth 

 edges. Anal small, and posterior to the second dorsal. Tail with a 

 keel on its sides ; lobes not greatly unequal. Length four to eight feet. 



Description. Body cylindrical, fusiform. Head small, with a blunt pyramidal snout six 

 inches long, measured from the nostrils. The surface, under the lens, exhibits numerous 

 minute plates, each with three parallel longitudinal elevated lines, producing a roughness when 

 the hand is moved towards the head. A carina on each side of the tail, about two feet in 

 extent, highest in the middle ; a deep indentation on the upper and lower sides of the tail, in 

 the shape of a horseshoe. On the surface of the head are four series of punctures on each 

 side, commencing nearly opposite to the posterior margins of the orbits, dilating and extend- 

 ing to within about an inch of the extremity of the snout. Immediately before the eyes is a 

 large patch of similar punctures, which extend slightly beyond the nostrils ; on the under side 

 of the snout is a triangular patch of similar punctures, extending to within 0*7 of the extre- 

 mity ; a regularly curved series of punctures from the end of. the carina, concurrent with the 

 back, and ending just anterior to the origin of the first dorsal fin. All these punctures are 

 the apertures of mucous ducts, which are filled with a transparent jelly. The skin, at the 

 posterior base of the dorsal and pectoral fins, was eroded by some parasitical animal. (Dr. 

 Storer noticed the Anthosoma smithii on his specimen.) Eyes moderate, lateral 2" 3 in dia- 

 meter, and eight inches distant from each other. Nostrils doubly curved, sublateral. The 

 posterior branchial aperture farthest from its antecedent. 



Teeth, of various shapes and sizes, disposed in from three to five rows. In the lower jaw, 

 the front teeth (see figure 206, 4) are largest, 0'9 long measured to the space between the 

 roots, irregularly lanceolate, the external and sometimes the internal edge rounded and waved ; 

 the margins with a finely elevated crest, which is smooth, obsoletely serrate under the lens ; 

 flattened in front, and rounded, approaching a triangular form behind ; occasionally they are 



