FISH. 153 



The lateral line, which is very distinct, commences behind the mouth, whence it passes under 

 and partly encircles the eye, then arches upwards, making a long sweep, and not descending 

 till it gets above the anal, whence it proceeds nearly along the middle towards the caudal, but 

 loses itself before attaining to that fin. Dorsal fin rather in advance of the anal. Caudal 

 square. 

 Colour. — " 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 

 described round the base of each pectoral. The abdominal streaks run very exactly parallel 

 with the axis 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. Honckenii of Ruppell,* but the colours 

 appear different. On the other hand, the markings resemble those of the T. tes- 

 tudineus of Bloch, but that species is rough all over. 



3. Tetrodon annulattjs. Jen. 

 T. dorso et lateribus nigro-fuscis, maculis circularibus atris ; infra niveus : corpore 

 oblongo, haud admodum ventricoso, ubique sed parch muricato, rostro et cauda 

 exceptis : capite grandiusculo, spatio interoculari lato, parum depresso : maxillis 

 subcequalibus : naribus cylindraceis, recumbentibus, aperturis duabus lateralibus : 

 lined laterali in capite tortuosissimd : pinna dorsali vix anali anteriore : pinna caudali 

 cequali. 



D. 8; A. 7; C. 9, &c. ; P. 15. 

 Long. unc. 9. 

 Form. — 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. 



The 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. Honckenii of Bloch ? 



X 



