OSTRACION UNDECIM-ACULEATUS.— Smith. 



Pisces. — Plate XVII. 



O. supra lucide ochraceus ; infra straminens ; pinnis subochraceis ; figura. quadrangulare, angulis aculeis 



armatis, quinque dorso, sex abdominis lateribus ; fissura. brancbiale angulata. 

 Longitudo a nasi apice ad extremitatem pinnse caudalis 6 unc. 



Colour. — Back and sides intermediate between ochre and straw-yellow, 

 the tint clear and semipellucid ; below straw-yellow or pale cream-yellow ; 

 fins the same colour as the back, only paler and without the lucid hue. In 

 many specimens the upper and lateral parts of the head and the lower 

 portions of the sides over the abdominal angles irregularly tinged with a dull 

 orange-coloured brown. 



Form, &c. — Figure quadrangular; the superior or dorsal side much 

 narrower than the inferior or abdominal side, and the lateral sides, in 

 regard of breadth, intermediate between the two. The angle at each side of 

 the back, formed by the junction of the dorsal and lateral sides, nearly 

 straight anteriorly, posteriorly convergent, and behind the dorsal fin forms 

 with its fellow of the opposite side a flat triangular and obtuse point, which 

 projects over the upper surface of the tail. The breadth of the dorsal side is 

 greatest at the points where the angles begin to converge, and each point is 

 armed with a short, pointed, horizontal spine. Besides those spines there are 

 three others on the back, one projecting anteriorly from each superciliary 

 ridge, and one about midway between the two first-mentioned, near the 

 centre of the back in front of the dorsal fin. Top of the head level 

 posteriorly, concave anteriorly, the concavity broad between the eyes, narrow 

 towards the hindhead ; the sides of head under the eyes compressed ; face 

 moderately broad and rounded, muzzle rather produced and projecting 

 slightly beyond the general slope of the face. Branchial opening angular, 

 and situated some distance behind a line let fall from the outer corner of the 

 eye. The lateral sides of the cuirass, which are slightly waved, diverge 

 from above downwards, and the abdominal angles, formed by the lateral and 

 under sides of the cuirass, anteriorly obtuse, posteriorly acute, and each 

 is armed with three short spines, the first situated about midway between 

 the nose and hinder extremity of the cuirass, the last at the extremity of the 

 latter, and the third about equidistant between these two: the direction 



