324 THE FAMILY OF EELS. 



very long time after the influence of the puhnonic heart is 

 entirely removed. The vessels which issue from the caudal 

 heart appear to have a particular distribution to the spinal 

 marrow;" but it is evident from the figure that the current of 

 blood is directed to, and not from the orifice or outlet forward 

 from the caudal heart; so that these smaller vessels collect the 

 blood into this organ, and do not distribute it. 



Another remarkable organization in this genus, or at least 

 in the Eel and Conger, but of which the use is as yet unknown, 

 is described by the Rev. W. Houghton, F.L.S., in the "Journal 

 of Microscopical Science," with a plate, vol. iv, N.S., but which 

 requires further investigation. He remarks that having been 

 occupied at intervals in dissecting a number of Eels and a 

 couple of Congers, he observed the invariable presence of 

 two subtriangular openings in the fleshy portion of the head, 

 just at its juncture with the spinal column. His first impression 

 in regard to the use of these orifices was that they were 

 connected with the auditory organs; but, he adds, although 

 Mr. Cholmondeley Pennell, in his work, "The Angler Natur- 

 alist," asserts the presence of an ear or auditory aperture 

 amongst the mucous pores about the head, from the most 

 minute examination of a large number of the heads of Eels, 

 he confidently affirms that no such auditory aperture exists. 

 Upon inserting a bristle in each of the orifices above 

 referred to, and clearing away the flesh, each bristle was found 

 to have traversed a closed-in tube in the skull, and to have 

 come out just above the bone of the orbit; but on close 

 observation they were found to have no connection with the 

 organ of hearing. These tubes are very slender, and each one 

 of them terminates in a membranous fold in the tissue just 

 beneath the skin, above the eye; which fold contains a thin 

 fluid, that does not bear any resemblance to mucus. It may 

 have some connection with the habits or faculties of these fish, 

 that the whole of the optic nerve does not proceed to be 

 joined to the optic lobe of the brain; but that portion of it 

 which passes to another part of the brain must be connected 

 with some other function besides that of discerning outward 

 objects. 



It is a character of this family to have also an air-bladder 

 of considerable size; at the middle of which is what may be 



