A Guide to the Study of Fishes, Volume 1 (of 2)

e or wanting, and that of hearing is muffled and without power of acute discrimination, if indeed it exists at all. According to Dr. Kingsley (Ve

ach nasal cavity has two external openings. These may be simple, or the rim of the nostril may be elevated, forming a papilla or even a long barbel. Either nostril may have a papilla or barbel, or the two may unite in one structure with two openings or with sieve-like openings, or in some degenerate types (Tropidichthys) with no obvious openings at all, the olfactory nerves spreading over the skin of a small papilla. The openings m

roof of the mouth, and is strengthened by cartilaginous rings, like those of the windpipe. In the lamprey the single median nostril leads to a blind sac. In the Barramunda (Neoceratodus) there are bo

cts them to it. It is known that flesh, blood, or a decaying carcass will attract sharks, and other predatory fish

aster cornutus Agassiz. Supposed a

phlichthys subterraneus Gir

re fishes or river fishes. At great depths, as a mile or more, where all light is lost, they may become aborted or rudimentary, and may be covered by the skin. Often species with very large eyes, making the most of a little light or of light from their own luminous spots, will inhabit the same depths with fishes having very small eyes or eyes apparently useless for seeing, retained as vestig

or India is "quite equal to that of a frog." It is known also that trout possess keen eyesight, and that they show a marked preference for one sort or another of real or artificial fly. Nevertheless the vision of fish

h, Anableps dovii Gill

special eyelid, moved by a set of muscles. The iris in most fishes surrounds a round pupil without much power of contraction. It is frequently brightly colored, red, orange, black, blue, or green. In fishes, like rays or flounders, which lie on the bottom, a dark lobe covers the upper part of the pupil-a curtain to shut out light from above. The cornea is little convex, leaving small space for aqueous humor. In two genera of

pnops murr

to cover the whole upper surface of the head, being modified as

(Osbeck). Bay of Tokyo, Japan; from nature. K.

tic nerves is describe

it has one eye on either side. As soon as it rests on the bottom it begins to lean to one side. The lower eye changes its axis and by degrees travels across the face of the fish, part of the bony interorbital moving with it across to the other side. In some soles it is said to pass through the substance of the head, reappearing on the other side. In all spe

us system. In the hagfishes, which stand next highest in the series, the eye, still incomplete, is very small and hidden by the skin and muscles. This condition is very different

e, but sometimes it lies near a fontanelle or opening in the skull above. In some fishes it is brought into very close connection with the anterior end of the air-bladder. The latter organ it is thought may form part of the apparatus for hearing. The arrangement for this purpose is especially elaborate in the carp and the catfish families. In these fishes and their relatives (called Ostariophysi) the two vestibules are joined in a median sac (sinus impar) in the substance of the basioccipital. This communicates

tra wilderi Jordan and Everma

us bodies, with enamelled surface and peculiar grooves and markings. Each speci

anchiostoma lanceolatum (Palla

tilaginous substance of the skull. There is a small canal extending to the surface of the sku

s, hagfishes, and lampreys it forms a capsule of relativ

t extremely doubtful whether fishes really hear at all, in a way comparable to the auditory sense in higher vertebrates. Recent experiments of Professor G. H. Parker on the killifish tend to show a moderate degre

or (grunter or snorer) is applied to several fishes, both sci?noid and h?muloid. The noise made by these fishes may be produced by forcing air from part to part of the complex air-bladder, or it may be due to grating one on another of the large pharyngeals. The grat

anes or power of motion. In some fishes certain parts of the palate or pharyngeal region are well supplied with nerves, but no direct evidence exists that these have a function of discrimination

trils. In the catfish the principal barbel grows from the rudimentary maxillary bone. In the horned dace and gudgeon the little barbel is attached to the maxillary. In other fishes barbels grow from the skin of the chin or snout. In the goatfish and surmullet the two chin barbels are highly specialized. In Polymixia the chin barbels are modified branchiostegals. In

seudupeneus maculatu

it is associated with sense of touch, and hearing as well, the internal ear being originally "a modified part of the later

and similar insensibility has been noted in the pike and other fishes. "The Greenland shark, when feeding on th

TNO

of hearing in fishes, America