18. TAGRUS. iHa 



a, b. 29" long : stufted. Hoiitinan's Abiolhos. 

 c, d. 22" long: stuffed. Iloutman's Abrolhos. 

 e, f. Half-grown : skins. Houtman's Abrolhos. 



Skeleton. — The maxillary bone is of nearlj' equal width in tiio 

 middle and at the extremities, and has the anterior edge sUghtly 

 emarginate ; the intermaxillary is joined to the posterior extremity 

 of the former, and has the posterior processes of moderate length, 

 rather shorter than the descending branch. The mandibulary is some- 

 what elevated, with a narrow free interspace between the articular 

 and dentary pieces ; there are four or five distinct openings of the 

 muciferous channel, which nms along its lower surface. The head 

 of the vomer is triangular, and has the anterior margins sHghtly 

 sAvollen. The turbinal bones are very long, tubiform, broadest pos- 

 teriorly, where they together form a sutiire, and divergent ante- 

 riorly, to receive the processes of the intennaxillaries. The prajor- 

 bital is quadrangular, not much narrower posteriorly than anteriorly, 

 and one-third longer than wide ; the remainder of the infraorbital 

 ring is narrow ; there is a concave plate at its inside to support the 

 eyeball from beneath, and joined to the entopteiygoid by a hammer- 

 like process. The axes of the limbs of the praeoperculum fomi an 

 obtuse angle ; the angle of the margin is rounded. There runs a 

 rather strong ridge parallel to the margins of the praeoperculum, with 

 a mdimentary muciferous channel and several distinct foramina. 

 The operculum is irregularly quadi'angiilar, with an interior ridge 

 descending obhquely in a backward direction. The suboperculmn is 

 nearly vertically situated and pointed above ; the iuteropercidum 

 with the lower margin rounded. The frontal bones are rather flat, 

 obHquely situated, their highest point being at their meeting -with 

 the occipital crest. The supraoocipital is horizontally situated, and 

 has a high triangular crest, the upper margin of which is swollen. 

 Of the lateral crests the outer one only is developed, and transformed 

 into a very distinct channel with about five openings. The base of 

 the skull is slightly compi'essed, and there is a wide cavity in the 

 basisphenoid before the occipital joint. The pubic bones are of mode- 

 rate length ; each is formed by three lamellse, the inner of which is 

 broadest. 



There are ten abdominal and fourteen caudal vertebra, the length 

 of the fomier portion of the vertebral column being to that of the 

 latter as 1 : 1"4. ITiere are three spurious interneural spines in front, 

 styliform ; nearly all the others arc chlated : the second is the longest, 

 the following gradually decreasing in length. The first interha?mal 

 is strong, and equal in length to the first seven vertebrae. Some of 

 the ribs have epipleiu'al spines. 



There are fom- canine teeth in both jaws. The molars are of 

 nearly equal size, and small ; two series in the up]ior jaw. In the 

 fewer jaw they are arranged in two series on llie middle part only 

 standing in a single series anteriorly and posteiiorly. 



