M Y T I L A C E A M Y X I N E . 



Thompson has published a very valuable Memoir 

 upon this genus in his Zoological Researches. 



MYTILACEA. De Blainville's fourth family of 

 the third order Lamellibranchiata : it includes the 

 genera My film and Pinna, third class, Acepfialophora. 



MYTILUS. (Lamarck, Linnaeus.) The genus 

 Mytilus, now consists of such examples of the Lin- 

 naean Mytili as are regular, eqnivalve, and longitudi- 

 nal molluscs, of a solid and riot a lamellar structure 

 (as in the oyster) : they have pointed apices at the 

 inferior end, nearly straight or slightly curved, and 

 attached to other substances by a byssus of a short 

 thick texture ; the cordinal ligament is lateral, and a 

 considerable portion of it internal ; by which, as well 

 as the different position of the apices, it is easily dis- 

 tinguished from its congeners. The Mytilus edules, 

 or common muscle, is so well known that a more de- 

 tailed description is needless ; it furnishes an abundant 

 and nutritious article of food, in some countries form- 

 ing nearly the only dependence of the inhabitants, as 

 an article of common food. The immense consumption 

 of this mollusc, in the London markets alone, exceeds 

 all calculation notwithstanding the prejudice existing 

 against them as sometimes possessing a poisonous 

 <jnalitv. It is not, however, the only shell-fish which 

 produces bad effects on certain persons ; and it is 

 probably occasioned by a peculiar state of disease in 

 the animal. Every known part of the world pro- 

 duces what are familiarly termed muscle?, and their 

 abundant distribution indicates their goodness as food 

 for man, since Supreme Wisdom has ordained that 

 everything noxious to life is far less productive than 

 those creatures which are not injurious, and intended 

 to be eaten. 



MYXINE Hag. A genus of Chondroptcry- 

 gcuus, or cartilaginous fishes, with h'xed gills ; and stand- 

 ing as it were on the very verge of the vertebrated 

 animals, and forming a sort of link between them and 

 the mollusca. For this reason, though the fishes 

 themselves are of uninteresting appearance and small 

 size, and perfectly useless in an economical point of 

 view, they are highly interesting to the student of 

 nature. They belong to the family of suckers, or 

 <-i/rlostonta, following in order the lampreys and the 

 sand-eels, to which they have several points of resem- 

 blance. They are, however, so nearly destitute of 

 anything which can be called a skeleton, so destitute 

 of eyes, of jaws, and all the other characteristics of 

 more typical vcrtebrata, that naturalists were for a 

 long time puzzled where to place them in the system. 

 This puzzle was further increased by the situations 

 in which these fishes are usually found, which is gene- 

 rally in the interior of cod and other voracious fishes, 

 upon which they fasten with their sucking mouth, 

 and consume the substance with no ordinary degree 

 of rapidity. The fact of their being found there, 

 with the uncertainty of their mode of increase, led 

 several naturalists, and among others the justly-cele- 

 brated Linnaeus, to conclude that they are Entozoa, or, 

 as he called them, " intestinal worms " This is not the 

 only mistake which has been committed relating to 

 entozoa and fishes ; for there is a tolerably large and 

 very peculiarly-shaped parasite, which breeds in the 

 intestines of eels, burying its head between the coats, 

 and extending its body along the canal. Now this 

 species of entozoa was long considered as the young 

 of' the eel ; and, for no other reason than that it is 

 subject to " worms in the belly," the eel was set clown 

 as a viviparous animal, or one which brought forth its 



young alive ; nor was it til! after Mr. Yarrcll had 

 exhibited one sex of the eel with melt and another 

 with roe, again the roe ready for spawning, and yet 

 again the " shotten" eel, Ilaccid from the newly-dis- 

 charged spawn, that "the learned" gave up this most 

 singular prejudice. Singular indeed it was, and at 

 violence with every known law of physiology ; for 

 though there are recorded instances of extra-uterine 

 gestation, there is no instance whatever of the young 

 of any animal coming to maturity, or at all existing 

 in the intestinal canal. That canal is the avenue of 

 death to every living thing that enters it, or if it is 

 not death to the enterer, it is certainly death to the 

 animal entered. This fact is universal, and appli- 

 cable to the whole of animated nature ; so that, 

 whenever any hypothesis is contrary to it, we require 

 no argument and no investigation to convince us that 

 that hypothesis is utterly without foundation. 



The myxine is an animal certainly well calculated 

 to perplex systematists, as it combines some of the 

 characters of the fish with some of those of the 

 cephalopoda, or order of mollusca, which, in their 

 genera! structure, make the nearest approach to the 

 vertebrated animals of any that are to be found 

 among the invertebrated ones. The external ap- 

 pearance indeed resembles a worm more than any- 

 thing else ; but even here the possession of a fin would 

 determine it to be a fish, although there were no more 

 decided characters founded upon its internal structure. 

 Perhaps we shall place this curious subject more 

 clearly before our readers by quoting, from Mr. 

 Yarrell's " History of British Fishes," his very clear 

 and satisfactory description of this singular animal. 

 " The body, " says Mr. Yarrell, " is elongated, eel- 

 like in form, cylindrical throughout the greater part, 

 of its length, tapering and compressed towards the 

 tail ; the whole length from twelve to fifteen inches ; 

 the skin perfectly smooth and unctuous ; the head 

 obtusely pointed ; with a single spiracle connected 

 with the mouth and branchue ; eyes wanting ; eight 

 tentacula, cirri, or feelers, as they are called, are 

 placed about the lips, four near the front, and two on 

 each side ; lips soft, extensible, inclining to a circle 

 in their figure ; one single-hooked tooth on the pa* 

 late ; the tongue furnished with four rows of small 

 pointed teeth, two rows on each sidy ; at the division 

 between the thoracic and abdominal cavities are two 

 external apertures, each of which is connected by a 

 membranous tube with the six branchia? of its own 

 side ; hence Bloch's name of Gastrobranchus. The 

 anal aperture is an elongated fissure, situated about 

 two inches before the end of the tail ; along the whole 

 surface of the body are ranged two rows of pores, 

 which afford egress to- the secretion of the numerous 

 glands within ; the dorsal fin is low and rudimentary, 

 except towards the tail, where the membrane is di-t 

 lated, and being continued round the end of the tail; 

 and thence upwards to the anal aperture, forms, in adt 

 dition, a caudal and anal fin, which no doubt materU 

 ally assist the fish in swimming. In colour the 1 

 myxine is dark brown along the back, lighter chestnut 

 brown on the sides, and yellowish white underneath." 



There are two species of this singular genus of 

 fishes, or perhaps, rather, we ought to say that there 

 are two genera or sub-genera, and that these extraor- 

 dinary creatures form a group in nature. The most 1 

 accurate systematists distinguish them by the num- 

 ber of breathing apertures in the sides ; and, of the 

 two which are known, one has seven such opening* 



