The Grayling and the Smelt 357 
enlarged, and the ventrals are well forward. The dorsal fin, 
inserted well forward, has stout basal bones. Chirothrix libani- 
cus of the Cretaceous of Mt. Lebanon is remarkable for its exces- 
sively large ventral fins. Telepholis is a related genus. Exo- 
cetoides with rounded caudal fin is probably the type of a 
distinct family, Exocetotdide, the caudal fin being strongly 
forked in Chirothrix. The small extinct group of Rhinellide is 
usually placed near the Myctophide. They are distinguished 
by the very long gar-like jaws; whether they possessed adipose 
fins or luminous spots cannot be determined. Rhinellus fur- 
catus and other species occur in the Cretaceous of Europe and 
Asia. Fossil forms more or less distinctly related to the Mycto- 
ay 
’ Fie 264 —Rhinellus furcatus Agassiz. Upper Cretaceous of Mt. Lebanou. 
(After Woodward.) 
phide are numerous. Osmeroides monasterit (wrongly called 
Sardinioides), from the German Cretaceous, seems allied to 
Myctophum, although, of course, luminous spots leave:no trace 
among fossils. Acrognathus boops is remarkable for the large 
size of the eyes. 
Maurolicide.— The Maurolicide are similar in form and 
habit, but scaleless, and with luminous spots more highly 
specialized. Maurolicus pennanti, the “Sleppy Argentine,’’ is 
occasionally taken on either side of the Atlantic. Other genera 
are Zalarges, Vinciguerria, and Valenciennellus. 
The Lancet-fishes.—The Plagyodontide (Alepisauride) con- 
tains the lancet-fishes, large, swift, scaleless fishes of the ocean 
depths with very high dorsal fin, and the mouth filled with 
knife-like teeth. These large fish are occasionally cast up by 
storms or are driven to the shores by the torments of a parasite, 
Tetrarhynchus, found imbedded in the flesh. 
It is probable that they are sometimes killed by being forced 
above their level by fishes which they have swallowed. In 
such cases they are destroyed through the reduction of pressure. 
Every part of the body is so fragile that perfect specimens 
are rare. The dorsal fin is readily torn, the bones are very 
