1 84 9 . J Catalogue of Malayan Fishes. 1349 



widest part of the back, appears on each side a small pointed tubercle, 

 between which the distance equals the length of the head. The centre 

 of the back is raised, so as to form a linear sharp keel which terminates 

 in a small pointed tubercle in the middle between the two lateral ones. 

 The abdominal surface is both longitudinally and transversely arched ; 

 the greatest transversal diameter, about the middle, is contained 2f times 

 in the total length. On each side of the termination appears a spine 

 resembling the frontal ones, but pointed in an opposite direction and a 

 little shorter. The armour is composed of pentagonal, hexagonal or 

 heptagonal pieces with the margins finely toothed or ciliated. The pieces 

 of the back and sides have each a tubercle in their centre, from which 

 radiate a number of lines corresponding to the respective number of sides. 

 On the pieces of the abdomen appear instead of lines a number of minute 

 hemispherical tubercles. The dorsal fin is placed at a short distance 

 from the termination of the armour above ; its length is J of the head ; 

 the extent of the base is ^ of the length. The length of the small naked 

 tail is contained about 2\ times in the elongated oval caudal fin. The 

 rounded anal is situated above, yet between the posterior pair of spines, 

 behind the dorsal which it resembles. The rounded pectorals are nearly 

 f of the length of the head. The smallest individuals examined measured 

 1 inch in length. They had no spines, but in their places appeared 

 tubercles. The central and lateral tubercles of the back were compa- 

 ratively more developed than in the adult. In the middle of the upper 

 pupillary margin of the iris appeared a small notch. The smallest 

 ones, provided with blunted spines half the length of the head, mea- 

 sured If inch in length. Young individuals are at Pinang numerous 

 at all seasons. 



Ostracium tesserula, Cantor. 

 Plate VIII. Fig. 2 and 3. 



Young. Armour bright gamboge with numerous small black spots, 

 not corresponding to the centre of the polygons, and fewer and more 

 distant on the abdomen ; tail bright gamboge with one or two black 

 dots on each side of the root of the caudal ; fins gamboge, a little paler 

 than the body ; pectorals with a single black dot at the root ; caudal 

 with the posterior margin pale blackish. Pupil transversely oval, black ; 



