The True Sharks 1gI 
shark, or Lammna, as distinguished from the blue sharks and 
white sharks allied to Carcharias (Carcharhinus). 
The Lamnoid sharks agree with the cat-sharks in the absence 
of nictitating membrane or third eyelid, but differ in the an- 
terior insertion of the first dorsal fin, which is before the ven- 
trals. Some of these sharks have the most highly specialized 
teeth to be found among fishes, most effective as knives or as 
scissors. Still others have the most highly specialized tails, 
either long and flail-like, or short, broad, and muscular, fitting 
the animal for swifter progression than is possible for any other 
sharks. The Lamnoid families are especially numerous as 
fossils, their teeth abounding in all suitable rock deposits from 
Mesozoic times till now. Among the Lamnoid sharks numerous 
families must be recognized. 
The most primitive is perhaps that of the Odontaspidide 
(called Carchartide by some recent authors), now chiefly ex- 
tinct, with the tail unequal and not keeled, and the teeth slender 
and sharp, often with smaller cusps at their base. Odontaspis 
and its relatives of the same genus are numerous, from the 
Cretaceous onward, and three species are still extant, small 
sharks of a voracious habit, living on sandy shores. Odon- 
taspis littoralis (also known as Carcharias littoralis) is the com- 
mon sand-shark of our Atlantic coast. Odontaspis taurus is 
a similar form in the Mediterranean. 
Family Mitsukurinide, the Goblin-sharks. — Closely allied to 
Odontas pis is the small family of Mitsukurinide, of which a single 
living species is known. The teeth are like those of Odontaspis, 
but the appearance is very different. 
The goblin-shark, or Tenguzame, Mitsukurina owstoni, is a 
very large shark rarely taken in the Kuro Shiwo, or warm “ Black 
Current’”’ of Japan. It is characterized by the development 
of the snout into a long flat blade, extending far beyond the 
mouth, much as in Polyodon and in certain Chimeras. Several 
specimens are now known, all taken by Capt. Alan Owston 
of Yokohoma in Sagami Bay, Japan. The original specimen, 
a young shark just born, was presented by him to Professor 
Kakichi Mitsukuri of the University of Tokyo. From this 
our figure was taken. The largest specimen now known is in 
the United States National Museum and is fourteen feet in 
