18 ZOOLOGY OF THE VOYAGE OF H.M.S. SAMARANG. 



There is also a series of four deep black marks, or bars, on the sides, viz., one under the eye, 

 another before the gill-opening, the third and largest under the pectoral, and the fourth 

 rather before the dorsal. The ground colour of the back deepens slightly over these marks, 

 as if in the recent fish they had formed the extremities of transverse dorsal bands ; but they 

 cannot be said to be mere prolongations of the ground colour into the white of the sides, 

 such as the lateral bars of the Uspidus of Bloch are described to be. When the skin is 

 examined with a lens, it is seen to be composed of tessellated minute plates, having various 

 forms in different parts. On the smooth skin of the tail they are round or polygonal. They 

 are oblong, but very unequal on the back, and smaller, granulated, and irregular on the belly. 

 Hab. Eastern Atlantic. 



TETRODON NARITUS, Richardson. 



Radii.— D. 33 ; A. 28; CIO; P. 17. 



Plate VIII. Eig. 1-3. 



The usual number of rays in the dorsal fin of a Tetrodon is nine or ten. One species, 

 the nigro-pvMctatus, is noted by Schneider as having only seven rays in that fin, in others the 

 numbers amount to twelve or thirteen ; but out of twenty-four species characterized by the 

 author just named, only one is said to have as many as fifteen dorsal rays. 1 The species 

 described below has more than twice that number of rays in the dorsal, and its anal is also 

 proportionably great. It differs also from any other fish we have seen in its nostril, which is 

 single and has an orifice equal in extent to the length and breadth of the cavity. 



The length of the head, measured to the gill-opening, is one fourth of the whole length 

 of the fish, caudal included ; the breadth of the head is less, being contained five times and 

 a half in the whole length. The eye is placed above the level of the mouth, and mid-way 

 between the end of the snout and gill-opening. The nostril is before, and rather higher than 

 the eye, and is a single, wide opening, with a smooth bottom, and a plaited, loose margin, 

 which forms two small, narrow, obtuse lobes anteriorly, the border being deficient between 

 the lobes, so as to form a small channel or notch on the anterior rim of the opening. The 

 mouth is rather small, the lips granulated or papillated on the edges ; and within close to the 

 teeth, there is a narrow, prominent, more densely papillated ridge. The mouth is terminal, 

 and the profile is gibbous over the eye. The belly is capable of considerable distention, so 

 as to assume a semi-globular form. The tail, between the three vertical fins, has a peculiar 

 shape, arising from an osseous enlargement of the upper and under interspinous bones, each 

 about the size of a kidney bean. The dorsal and anal fins have a different shape from those 

 of any other Tetrodon which we have seen, being longer than high, and considerably arched. 



The skin is smooth on the back, and of a pale brownish-purple tint, with various 

 reflexions, when taken from the spirits. The recent colours were not noted. The skin is 



1 This is the Chinese ocel/atits, which has usually only fourteen rays in the dorsal. 



