Photo by A. S. Rudland & Sons.
BOTTLE-NOSED CHIMÆRA.
The remarkable structure in front of the mouth is probably an organ of touch.
Shark-like in their general characters, the Chimæras, now briefly considered, are nevertheless regarded as constituting a very distinct group of great antiquity.
The modern representatives of the group are few in number—five species in all. Of these, the species shown in the accompanying photograph and the Sea-cat are remarkable for the possession of a movable tentacle on the snout. The under surface of this tentacle is armed with small spines, and fits into a hollow in the head. The first back-fin is supported in front by a strong spine, and can be depressed into a sheath in the body-walls. The teeth take the form of large plates closely united with the jaws, and studded with hardened points, or "tritors."
One species widely distributed in the Mediterranean and Atlantic is taken usually in deep water; it is the largest living species, often attaining a yard in length. Its occurrence is, however, very erratic, months elapsing without any being taken; at other times several will be caught in a few days. A closely allied fish is often exposed for sale in the Lisbon markets, where it ranks with the Sharks as a food-fish.
The egg of the Bottle-nosed Chimæra is perhaps the only egg with a mimetic resemblance to a foreign object. It is elliptical in form, and bordered by a fringe, so as to present a close resemblance to a piece of seaweed.
In the next chapter we begin the description of the great group of Fan- and Fringe-finned Fishes, which, briefly, embrace all fishes not grouped among the Lung-fishes, Chimæras, or Sharks. The anatomical characters used for the purpose of classifying this great group are not discussed here, save only in a few cases of prime importance, when features such as can readily be observed, without demanding an intimate knowledge of anatomy, are selected.
