NICHOLS iV Ml KI'IIV 
I.ONC. ISLAND SHARKS. 
round and round it. Pilot fish exist also in an inde])endent \va\-, that is, 
dis.sociated from sharks, but whenever they acconi]mn\- tlie latter, the\ 
follow their uncon.scious protector closely, rarel>- leax-ini; it for nian\ 
seconds at a time. Occasionalh* the}- dart aside for a morsel of food, but 
hurr}' back again like children afraid of losing their nurse. A favorite 
position with the jiilots is clo.se alongside the shark's dorsal fin, but 
.sometimes tlie\- swim beneath their big companion. 
Other fishes than the true jiilots sometimes fill the same role with re- 
lation to sharks. One of the writers once saw a blue shark accompanied 
by a veritable enveloi)ing cloud of young blue-lined runners ( /t/agatis 
bipinnulahis^ , a species which occasionally reaches the coast of Long 
Island. 
5. DUSKY SHARK 
Carcharhinns obsairus (Le Sueur) 
Jordan and Evermann, p. 35. 
Garnian, p. 130. 
First donsal fin much larger than second dor.sal and opposite space between 
pectoral and ventral fins, nearer to the pectorals. The fin much lower than in 
milberti and placed slightly farther back. Snout moderate, blunt. Angle of mouth 
with groove little developed. Teeth finely serrate ; the upper broad, triangular, 
inclined outward, with a concave outer margin. Lower teeth narrow, erect, on broad 
bases. Color brownish gray above, whitish below, sometimes said to be blue 
Length 6 to 10 feet. 
The du.sk\- shark is not rare on our Atlantic Coast, and is doubtless 
of frequent occurrence in Long Lsland waters. Its exact .status here is 
not known owing to the ease with which it may be confu.sed with 
Carchar/iinus viilberti. xA shark eight feet nine inches long, ])robably of 
this species, was once harpooned and captured by Mr. A. H. Helme in 
the Sotind off Miller Place. 
