556 PISCES—FISHES. 
rakers attached to the branchial arches and serving as 
‘strainers; they prevent the food from being swept out 
with the respiratory current. The gullet leads into a 
curved stomach ; at the junction of stomach and duodenum 
numerous tubular pyloric czeca are given off; into the duo- 
denum opens the bile-duct from the gall-bladder and liver; 
the coiled intestine passes gradually into the rectum, which 
has an aperture apart from those of the genital and urinary 
ducts. There is no spiral valve, and 
there are no abdominal pores. A 
pancreas is absent ; perhaps the py- 
loric ceeca take its place. (In some 
Teleosteans the pancreas, apparently 
absent, is combined with the liver.) 
The peritoneum is darkly pigmented. 
Respiratory system.—Water that 
passes in by the mouth may pass 
out by the gill-clefts; the branchial 
chamber is also washed by water 
which passes both in and out under 
the operculum. The gill-filaments 
borne on the four anterior branchial 
arches are long triangular processes, 
whose free ends form a double row. 
As there are no partitions between 
the five gill-clefts, the filaments pro- 
ject freely into the cavity covered by 
the operculum. On the internal 
surface of the operculum lies a red 
patch, the pseudobranch or rudi- 
Section ofa mentary hyoidean gill. Inspiration 
Ba aay . and taking food into the mouth 
G.F,, Gill-filament; A., artery are associated with the retraction of 
Gengua nog) eR imgaues the hyoid apparatus ; expiration and 
swallowing are associated with the 
protraction of the hyoid arch. The usual retractor of the 
lower jaw is absent in Teleosts, and the lowering of the lower 
jaw comes about automatically in the retraction of the hyoid 
arch and the raising of the operculum,—in short in the 
inspiratory phase. A large and quaint parasitic copepod— 
Lernea branchialis—is often found with its head deeply 
