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Show 152 ZOOLOGY OF TilE VOYAGE OF TilE BEAGLE. ] • TETRODON AEROSTATICUS. Jen. T. 'b t . a caudali nigro-rnaculatis; ventre lut'gidissimo, capite, dorsa, laterz tts, e puw ' · . .. bl' ·8 n•n·rt's. corpo1·e undique muricato, cauda solutn excepta: captte fascu·s 0 tqttt · ·~ . z z lum denresso : maxillz.s r£q·ua l'b l' a l z· t us : zne atera t b1'evz · fronte znter octt os pau u r . nulla': pinna dorsali omnino ante analem posita : pinna caudalt subrotundata. D. 11; A. 10; C. 10; P. 11. LoNG. unc. 2. lin. 6. l!'onM.-Ilead short. Body approaching to globular, with the skin .of the bell!. extremely loose and ca able of great inflation; every where beset with minut~ pnckly aspeutlCs, the extreme end o/the tail alone excepted. Crown nearly flat, very shghtly depressed be.twecn the eyes. J aws equaU y ad vance d . Nostrils tubular· No appearance of any lateral lmc. Dorsal en-tirely in advance of the anal: both these fins small. Caudal slightly round~d. CoT,OUR.-(.b~ spirits.) Head, back, and sides to the depth of the pectorals,_ greyish brown, spotted with black; the spots very small and crowded on the back, b_ut beco~ng. larger on the flanks and tail. Belly white, with deep black oblique broad bands, mosculatmg m some places, so as to form large meshes. Dorsal, anal, and pectorals, plain; but the caudal very elegantly and distinctly spotted. The ticket attached to this specimen has been lost, and its locality is in con-sequence unknown. In general appearance, .it very mu.ch resembles the ~.li~e~tus of Bloch, of which it may possibly be a var1ety; but It would seem to dlffe1 ft~m that species, in having the forehead less elevated ; in wanting the lateral lme altogether, of which I can discover no trace; and in having tl~e whole b_ack and upper part of the sides spotted, and not merely the tail and 1ts fin, as IS repre-sented in the T. lineatus. 2. TETRODON IMPLUTUS. Jen. T. sm·dide rnetallico-olivaceus, maculis ci1·culm·ibus albis; ventre albo, lineis olivaceis longitudinalibus, ltaud admodurn turgido: corpore suboblongo, magna e~ pa~·te lcev~s~ simo, ventre solum muricato: maxillis subcequalibus: nm·ibus tubuloszs, bifu1'calts · linea laterali distinct a, pm·um lortuosd : pinna do1·sali anali paulo anteriore : pinna caudali cequali. D. 10; A. 10; C. 11; P. 16. LoNG.unc. L lin. 9. FoRM.-Approaching to oblong, the belly a little ventricose. IIead not so short as in the last species, nor yet much produced. Body every where smooth, excepting the middle of the abdomen from beneath the pectorals to the vent, and not very prickly here. Top of the head slightly depressed between the eyes. Jaws nearly equal ; the upper one, if any thing, a very little in advance. Nostrils tubular, the tubes forked from the bottom into two equal branches. FISII. 153 The lateral lin~, which is !Very distinct, commences behind the mouth, whence it passes under ~nd: partly encircles the eye, then. arches upwards, making a long sweep, and not descending t1ll1t _gets above the a?~l, whence It proceeds nearly along the middle towards the caudal, but loses 1tself before attammg to that fin. Dorsal fin rather in advance of the anal. Caudal square. CoLoun..-" Dirty metallic olive-green, with white circular spots ; belly white, with streaks of the same colour as the back."-D. The spots extend on to the basal half of the caudal, but are smaller here than on the body. A white annulus encircles each eye, and a similar one is d~scribed r~und the base of cac~ pectoral. The abdominal streaks run very exactly parallel With the axts of the body, not obliquely as in the last species. Habitat, Keeling Islands, Indian Ocean. I can find no species noticed by authors exactly corresponding with the one described above, which was obtained by Mr. Darwin at the Keeling Islands. The form is similar to that of the T. Honclcenii of Riippell, • but the colours appear different. On the other hand, the markings resemble those of the T. testudineus of Bloch, but that species is rough all over. 3. TETRODON ANNULATUS. Jen. T. dorso et lateribus nigro-fuscis, maculis ci1·culm·ibus atris; infra niveus: c01pore oblongo, ltaud admodum ventricoso, uhique sed pm·ce muricato, rost1·o et cauda exceptis: capite grandiusculo, spatio interoculm·i lato, pa1·um depresso: maxillis subClJqualibus: na1·ibus cylindraceis, recmnbentibus, aperturis duahus lateralibus: linea laterali in capite tortuosissimd: pinnd dm·sali vix anali anteriore: pinna caudali ([!quali. D. 8; A. 7; C. 9, &c.; P. 1.5. LoNG. unc. 9. FonM.-Oblong: head rather large; the snout a little more produced than in the last species. Moderately ventricose, and apparently capable of a certain degree of inflation. No where perfectly smooth, except on the snout, tail, and here and there on the flanks; nor very rough, the prickles being minute and rather scattered, most apparent on the back, nape, (whence they advance to quite between the eyes,) and the middle of the abdomen. The interocular space is broad, equalling two and a half diameters of the eye at least, and a little hollowed out. Jaws nearly equal, the upper one perhaps a very little in advance. Nostril in the form of a small recumbent cylinder, with an opening at each extremity. Dorsal very little in advance of the anal; the first ray in each of these fins very short. Caudal square. Tho lateral line is very tortuous, especially about the head. It commences at the bottom of the gill-cover, whence it ascends vertically behind the eye towards the crown, then passes over the eye towards the snout, descends again beneath the nostril to form a great loop in front of the eye, almost reaching to the corners of the mouth, whence it returns beneath the eye, • Surely this cannot be the same as the T. Uonckenii of Bloch 1 X |