150 



hahdwicke's science-gossip. 



[July 1, 1869. 



unguarded, water flows in and fills the chamber of 

 the capsule (e) by the simple action of gravity; this 

 water bringing with it foreign bodies, could never be 

 expelled or changed, but for the contractile mus- 

 cular pouch lying below. When this is compressed by 

 the will of the animal, the water it contains is forced 

 out in a strong jet through the narrow neck and 

 literally syringes out the smelling-chamber and 

 upper tube. The Lamprey is thus enabled " se 

 emungere" and to change the water as often or as 

 seldom as it pleases, with quick successive sniffs 

 when smelling about for food, and at longer inter- 

 vals when in a state of rest. The fact that "currents 

 of water have been observed to enter the nasal 

 orifice" may perhaps have led some people to jump 

 to the erroneous conclusion that they must have 

 been passing to the gills. 



At (/) we see the brain enclosed in the remarkably 

 small cranium, " the proper cranium, which is a 

 kind of cartilaginous box, closed in front, and 

 through the greater part of its roof, only by mem- 

 brane, but complete behind, where it arches over the 

 myelon and is perforated by the occipital foramen." 

 At (Ji) we see the intervertebral markings of the 

 chorda dorsalis, and at (i) the rudimentary spinous 

 processes ; at (£) the transverse cartilage of the 

 tongue ; at (/) the anterior piston-like portion of the 

 tongue with the teeth of its nearly circular saws ; 

 (m) marks the soft commissure of the lip ; {n) the 

 elongated lingual cartilage, which performs the part 

 of a piston-rod ; (o) the right epiglottidian cartila- 

 ginous valve closing the anterior orifice of the 

 branchial channel and preventing the regurgitation 

 of water through the mouth ; (q) the central respira- 

 tory chamber or branchial channel, in which three 

 of the internal openings (to) of the gill-chambers are 

 seen ; (r) soft fibrous basis of the lip in section ; (s) 

 principal teeth in connection with the oral ring ; (t) 

 zone of mucous papilla? just within the margin of 

 the lip ; (u) basi-occipital plate ; immediately behind 

 the nasal tube and above the olfactory capsule is a 

 reddish fibrous and elastic mass (x) apparently 

 glandular, of the size of a hazel-nut ; the external 

 skin above this body is thinned, devoid of pigment, 

 and perforated by a minute orifice. 



The specimen from which this drawing was taken 

 measured thirty-four inches in length, and eight 

 inches rouud the thickest part of the body over the 

 gill-openings. The largest specimen seen in Glou- 

 cester within the last fifty years is said to have 

 measured thirty-nine inches. 



When Lampreys were in fashion, they fetched 

 about ten shillings each in the early part of the 

 season, i. e. in May ; but they are no longer the 

 rage, and are sold at about the average market 

 price of common eels. I paid only half a crown for 

 each of mine, and they were very fine, weighing 

 over four pounds apiece. They are usually taken 

 in the salmon nets, and arc in season from the 



middle of April until the middle of June, after 

 which time they return to the sea. The fishermen 

 have an opinion that all the Lampreys they catch 

 are invariably one year old. There seems to be no 

 ground for such a conclusion; from the great variety 

 in size and weight— from one to four pounds— we 

 may suppose that their ages differ considerably and 

 that the larger specimens are probably several years 

 old. 



The Lamprey, ugly fellow though he is, has had 

 his praises sung in Latin verse ; there is a scholarly 

 account of his classical history in an article by Mr. 

 Couch in vol. ii. of the "Intellectual Observer." 



We appear to have but one species of Lamprey in 

 England ; there is another found in Erance : there 

 are four American varieties, and a hideous monster 

 " the Pouched Lamprey of Australia." 



The pouch is said to be a provision of nature for 

 enabling the creature to store a supply of water to 

 enable it to endure the long droughts which often 

 dry up the streams it frequents, when it burrows in 

 the mud and remains in a semitorpid condition 

 until the return of the rains. 



This pouch exists in a rudimentary state in our 

 P.marinus; but as the latter is not subjected to the 

 same vicissitudes as its Antipodean representative, 

 nature suppresses the development of an appendage 

 which would only be a useless incumbrance to it. 



The so-called "Mud Lamprey," or "Sand 

 Pride," is not a true Lamprey, Petromyzon j it does 

 not possess the power of adhering to foreign bodies 

 by the mouth, and properly belongs to the genus 

 Ammocates : it is the Lamprillon of Cuvier. 



I have but little space left for the Lampern, 

 Petromyzon (vel Lampetra) fluviatilis, the River 

 Lamprey, as it is sometimes called ; la petite Lam- 

 prgie of Cuvier. In structure as well as in its 

 habits it closely resembles its larger congener, but 

 is only from seven to ten inches in length, and from 

 an inch to an inch and a half in circumference, and 

 weighs about a couple of ounces. The skin is quite 

 smooth, of a blue colour on the back and sides, 

 maculis carens, without the mottled spots of P. 

 marinus, passing into a silvery white underneath. 

 The armature of the mouth differs very materially 

 from that of the larger genus. " Lampetra fluviatilis, 

 upper and lower teeth transverse, crescent-shaped ; 

 labial teeth in two submarginal rows ; inner lateral 

 teeth larger, two- or three-lobed ; lingual teeth 

 pectinate." This fish is found in abundance in 

 British rivers ; it is caught from July to March in 

 baskets called " Lampern putchers," and sold by 

 the hundred at a very low price : it is chiefly used 

 for bait for sea-fishing. 



The Fringe - lipped Lampern, Petromyzon Pla- 

 ned, is shorter and thicker than P. fluviatilis; 

 it is found chiefly in the Scotch rivers ; it seems to 

 be unknown in the Severn. The teeth are somewhat 

 differently disposed, but it is chiefly distinguished 



