XII STENO AND TURSIOPS 379 
the Camaroon river, where it is extremely rare. The nostrils 
(blow-hole) are prolonged into a snout-like process, a fact which is 
of interest in connexion with the assertion that in Balaenoptera 
the blow-hole is puffed out during spouting. What is temporary 
in the Rorqual appears to be permanent in the Sofalia. More 
remarkable still, perhaps, is the assertion that it is a vegetable- 
feeding Dolphin. This is not a mere assertion except that it 
may not apply universally; for in the stomach of a specimen 
nothing but vegetable débris was found. But in the stomachs of 
other Whales (e.g. Rhachianectes) vegetable matter has also been 
found, which may perhaps have been taken in accidentally with 
the food. 
Steno comes near Sotalia, and Dr. Blanford has transferred 
to it (under the one name of Steno perniger) the two species, 
Sotalia gadamu and Sotalia lentiginosa. It is, however, to be 
distinguished from Sotalia by the following characters :—Teeth 
large and few, twenty to twenty-seven on each side of each jaw, 
with furrowed surfaces to crowns. Vertebrae C 7, D 12 or 13, 
L 15, Ca 30 to 32. Pterygoids in contact. There are but two 
species apparently (not counting Dr. Blanford’s). 
Tursiops is not a very easily definable genus. These 
are its chief features:—Teeth large, twenty-two to twenty- 
six in number in each half of each jaw. Vertebral formula 
Cr, D2 or 13; 16 or 17,(\Ca 27) Pterygoids in: contact. 
Beak distinct. Some five species are allowed; but it seems 
to be difficult to differentiate the others from Twursiops tursio. 
This, the best-known form, is quite or nearly world-wide in 
range, and occurs, though not abundantly, on our own coasts. 
Mr. True has observed that the eyelids of this Whale, which 
is largely hunted on the American coast, are as mobile as 
those of a terrestrial mammal. The name “tursio” is derived 
from Pliny. Belon would also derive from this word the 
French vernacular “marsouin.” The latter term is sometimes 
regarded .as a corruption of “ Meerschwein,” but it would seem 
to be more probably derivable from “ marinum suem,” from the 
Latin direct. 7. tursio has the back black to lead-colour; 
the under parts white. In the reputed species, 7. abusalam, 
from the Red Sea, the back is a dark sea-green. 7". tw7'sio reaches 
a length of 12 feet, but is more usually smaller. 
The genus TZwursio must be carefully distinguished from 
