194 ACANTHOPTERYGII.— FISTULARIADiE. 
lengthened, flattened sidewise, and coming to an 
edge along the back. They have only two or 
three gill-rays, which are slender. There are two 
dorsals, the flrst strongly spinous, and both placed 
far behind ; and small ventrals situated behind 
the pectorals. The mouth is very small and opens 
obliquely; the intestinal canal has two or three 
folds, but no cmcal appendages ; there is an air- 
bladder of considerable size. Ten species are 
comprised in this sub-family, forming two genera; 
they are scattered over the Atlantic and Pacific 
Oceans ; one is common in the Mediterranean, 
whence it occasionally wanders to the southern 
shores of Great Britain. 
Genus Centriscus. (Linn.) 
In this genus the form is short and compressed, 
the depth much exceeding the transverse diameter 
of the body ; the head is not far short of half 
the whole length, much produced into a slender 
tube : the mouth, opening at the extremity, is 
very small, and destitute of 4eeth. The first 
dorsal is situated far back, and contains three or 
four spinous rays, of which the first is large and 
strong, connected by intermediate pieces with the 
bones of the shoulder and the skull : being thus 
supported, and very stout and strong in itself, 
and armed with a series of rugged teeth along 
its hinder edge, this spine forms a powerful 
weapon of offence and defence, capable of being 
moved at the will of the animal. The ventral 
fins afe small and united. The body is covered 
with small scales, and with some larger toothed 
ones over the bony apparatus that connects the 
