ACANTHODERMA. 



these animals agree in all respects with the common porcupin 

 from which, indeed, 

 they only differ in the 

 general form or outline 

 of the cranium, and the 

 comparative develop- 

 ment of the bones of 

 the face and skull ; 

 characters which have 

 no very assignable in- 

 fluence upon the habits 

 and economy of animal 

 life. There has been 

 some difference among 

 zoologists as to the use 

 of this term. Thus, 

 Acanthion of F. Cuvier 

 is Acantherium of J. E. Gray, whilst the Acanthion of Gray include 



Skull of Acanthion. 



Skull of Porcupine. 



both the genera J/i/i/rijc (Porcupine) and Acanthion of F. Cuvier 

 (Wsterhoiue, A'o'/rnfio.) 



ACANTHODEHMA, a fossil genus of fishes, from Glaris. (Agassiz) 



ACANTHO'DES, a genus of fossil Ganoid fishes, established by M 



Agaasiz. The species occur in the carboniferous strata near Edin 



burgh. (Agassiz.) 



ACA'XTHOl'HIS (from tucatBa, a thorn, and fyis, a snake), in 

 jy, a genus of venomous serpents, allied to the vipers, but dis- 

 tinguished by having a single series of plates beneath the tail, except 

 towards the very extremity, where they are, in some cases, separatee 

 into two small rows. The bodies and tails of these animals are 

 elongated and cylindrical ; their heads round, obtuse, rather promi- 

 >ver the eyes, and covered in front with nine or ten polygonal 

 plates. The back and upper surface of the tail are covered with 

 reticulated scales of a rholnboidal form ; the breast and belly are 

 I with single transverse plates, as is likewise the tail, excepting 

 towards the very extremity, which is sometimes furnished with a 

 double row of plates, as in the common viper. The tail is terminated 

 by a little spur, or horny excrescence, which has suggested the name 

 of Acanthophii (that is 'thorn-snake') for this genus. It springs out 

 of the very end of the tail, and does not appear to be of the same 

 utility as the two horny spurs which grow upon each side of the anus 

 in the Pythons and Boas, and which, being retractile, or capable of 

 being erected and depressed at will, execute important functions in 

 the economy of these animals. 



Tail of Acanthophit. 



Tin- head of the Ara>i'/,f,j,/:;.i is bro;ul and compressed, the mouth 



le of great distension, and furnished on each side, besides the 



retractile poison-fangs common to all the family of truly venomous 



Her|'iitx, with a double row of sharp curved teeth. The species of 



nus aii of small .size, reside on the surface of the dry land, and 



ipon frogx, lizards, and small mammals. They are viviparous, 



crete themselves in rat-holes, or beneath the roots of trees. 



They never strangle or crush their prey by coiling themselves round its 



bo.lv, but expect a more speedy and certain victory from the deadly 



effects of their pnixon. The species best known are 



///,/.!> nratliniu, first described by Merrem, and so 



I from the general similarity which it bears, at firat sight, to 



the C'trcutei, or Horned Viper, in its short body, large flat head, and 



'iniiotintcd by prominent scales. The length of this species is 



which the tail measures rather more than a 



fifth part ; the body is thick in proportion to its length, having a 



NAT. HIST. DIV. VOL. I. 



ACANTHURUS. 



circumference'. 



gradually tapers towStjtes and a half in the 



this species is unknowTS^r extremity.' 



Acanthophis cerastitut.i. 



The A canthophu Brownii is briefly described by Dr. Leach, and 

 figured in the first volume of the ' Naturalist's Miscellany.' The 

 specific name is given out of compliment to Mr. Robert Brown, the 

 celebrated botanist, from whose manuscripts the brief description of 

 Dr. Leach was taken. The body is said to be of a uniform dark 

 brown, the under lip whitish, the upper with a transverse groove in 

 front, the tail small and rather abruptly contracted at its junction 

 with the body, and the apex compressed laterally. This is probably 

 the Death Adder, or Tammem, referred to by Mr. G. Bennett, in his 

 ' Wanderings in New South Wales.' It is a hideous and exceedingly 

 venomous reptile. 



ACANTHOPTERY'GII (from tucavBa, a thorn, and nWpv{, a wing), 

 in Zoology, one of the three primary divisions, or natural orders, of 

 fishes. The fishes are divided into three orders the Chondropteryyii 

 (from x^vfyoSt cartilage, and wrf'pu, a wing or fin), or cartilaginous 

 fishes, without a solid bony skeleton ; Acanthopferyyii, fishes having 

 lx>ny skeletons with prickly spinous processes in the dorsal fins ; 

 and Malacopteryyii (na\ait6s, soft, and trrtpu(, a wing), fishes with 

 aony skeletons indeed, but with soft articulated radii in the dorsal 

 ing. These divisions were first employed by Willughby and Ray. 



uvier divides the Acanthopterygious Fishes into fifteen natural fami- 

 ies, which he calls after the names of their typical or most common 



;enera. 



1. Per f idee, including the common Perch, the Sea-Perch, the Barber 

 of the Mediterranean, the Weevers, the Stargazers, and the Sea-Pike. 



2. Triylidte, which include the Gurnards, the Flying-Fishes, the Bull- 

 Heads, the Miller's-Thumb, and the Sticklebacks. 



3. Scicenidw, which include the Maigres, the Stone-Perch, the Drum- 

 leads, the Red-Throats, and a number of other fishes less known. 



4. Sparidff, including the Sea-Breams, the Spanish Bream, the Gilt- 

 riead, and Black Bream. 



5. Menidcr, a small family whose species are not much known. 



6. Sguamipenncs, including the Chsetodons and other curious fishes, 

 as the Coachmen, the Horsemen, and others. 



7. Scomberidfe include the Mackerel, the Tunnies, the Sword-Fishes, 

 he Pilot-Fishes, the John-Dory, and the King-Fish. 



8. Tanidce, including the Scabbard-Fish, the Hair-Tail, Red-Band- 

 ^ish, and others. 



9. Theittyes, including the Lancet-Fishes, and some other genera 

 remarkable for their powerful cutting spines. 



10. Anabada include the Climbing Perch and other allied fresh- 

 water fishes. 



11. Muyilidce include the Gray Mullet, the Ramando of Nice, and 

 ome others. 



12. Gvbioda include the Blennies, the Gobies, or Sea-Gudgeons, and 

 he Dragonet. 



13. LophiadcK include the Anglers, the Fishing-Frog, or Sea-Devil, 

 nd the Frog-Fishes. 



14. Labridoe include the Wrasses, or Rock-Fishes, the ' Old Wives of 

 lie Sea,' the Captains, and the Scarus. 



15. FMtdaridtf, include the Pipe-Mouths, the Snipe-Fish, the Sea- 

 'rumpet, or Bellows-Fish. 



ACANTHU'RUS (from &K<tvBo, a thorn, and oupd, a tail), a genus of 

 Vcanthopterygious Fishes. It contains a great number of species, 

 many of which are remarkable for the beauty of their external forms, 

 nd the variety of their colours. They are distinguished from proxi- 

 late genera by the form of the body and tail, which are exceedingly 

 ompressed ; by their trenchant teeth, denticulated like a very fine 

 omb j but above all by the moveable spines, edged and sharp like a 



