THE LANCELET. 



or sea-hare, which, when startled, stain the water with their protective secretion and 

 shoot off under shelter of the sudden darkness. 



Around the lips of the Myxine are eight delicate barbules, which are evidently 

 intended as organs of touch ; the mouth is furnished with a single hook tooth upon the 

 palate serving apparently as an organ of prehension, and the tongue is supplied with 

 a double row of smaller but powerful teeth on each side, acting on the principle of j 

 rasp The Myxine can scarcely be said to possess any bones, the only indication of 

 a skeleton being the vertebral column, which is nothing more than a cartilaginous 

 tube through which a probe can be passed in either direction. The structure of the 

 breathing-organs is very remarkable, but can be hardly understood without the employ- 



HAQ-F1SH, OR MYXINE. Myxine glutiaosa. 



ment of figures. Suffice it to say that a double row of branchial cells take the place of 

 gills or lungs, and are supplied with water through a spiracle in the upper part of the 

 head, and two little apertures on the under surface. 



The color of the Hag-fish is dark brown above, taking a paler tint on the sides, and 

 grayish yellow below. Its length is generally about a foot or fifteen inches. 



THE last of the fishes is a creature so unfishlike that its real position in the scale of 

 nature was long undecided, and the strange little being has been bandied about between 

 the vertebrate and invertebrate classes. Between these two great armies the LANCELET 

 evidently occupies the neutral ground, its structure partaking with such apparent 

 equality of the characteristics of each class, that it could not be finally referred to its 

 proper rank until it had been submitted to the most careful dissections. In fact, it 

 holds just such a. position between the vertebrates and invertebrates as does the 

 lapidosiren between the reptiles and the fishes. 



It has no definite brain, at all events it is scarcely better defined than in many of 

 the insect tribe, and only marked by a rather increased and blunted end of the spinal 

 cord. It has no true heart, the place of that organ being taken by pulsating vessels, 

 and the blood being quite pale. It has no bones, the muscles being merely attached to 

 soft cartilage, and even the spinal cord is not protected by a bony or even horny cover- 

 ing. The body is very transparent, and is covered by a soft delicate skin without any 

 scales. There are no eyes, and no apparent ears, and the mouth is a mere longitudinal 

 fissure under that part of the body which we are compelled, for want of a better term, to 

 call the head, and its orifice is crossed by numerous cirrhi, averaging from twelve to 



