11. COLLICHTHTS. 315 



sible to give a fiill description of it. Many bones are so thin, that they 

 are more like membranes ; and great portions of them, as for instance 

 of the frontal bones forming the roof of the skull, are reaUy replaced 

 by membranes. As in aU true Scicenidce, the body of the skull is fur- 

 nished by a superstructm-e of bony plates and bars, ■which, arranged 

 with architectonic symmetry, support the skin which covers the 

 whole, and form deep and regular cavities. I need not describe the 

 single cavities in tliis species, as they are very similar to those of 

 CoUkhthijs pama, figured by Cuvier*. The intermaxillaiy is elon- 

 gate, lanceolate, without any j^rominent posterior process ; the max- 

 illaiy has a round open space, not ossified in. its posterior half. The 

 vomer is situated more posteriorly than in those fishes which have 

 this bone armed with teeth ; it does not project into the ca^■ity of 

 the mouth, but is excavated, — a form, which, for systematical ar- 

 rangement, is much more important than the absence or presence of 

 vomerine teeth : a vomer with this structure is never armed with 

 teeth. The palatine bones are thin, short and broad, and have a 

 veiy delicate fi-ee margin. The lower part of the brain-capsule is 

 remarkably large and globular. 



There are eleven abdominal and eighteen caudal vertehrce, the 

 length of the former portion of the column being to that of the latter 

 as 1 : 1'75. The thii'd vertebra is fiu'iushed inferiorly with a pair- of 

 porous processes, forming together a broad knob, to which the air- 

 bladder is fixed. The interhsmal for the anal spines is slender, 

 feeble, and suspended at the haemal of the twelfth vertebra. 



2. Collichthys biaurita. 



Otolithus biauritus, Cantor, Catal. Malay . Fislies, p. 57 ; Bleek. Act. 

 Soc. Sc. Indo-Nederl. iii. Borneo, p. 3. 



I 27-32 7 



The height of the body is 6 j in the total length, the length of the 

 head 4|-4i ; the diameter of the eye is only one-eighth of the length 

 of the head. The upper jaw convex, overlapping the lower ; in both 

 the jaws are largei- teeth in the outer row, but canine-Hke teeth are 

 distinct in the upper only. Opercidar region with two skinny lobes, 

 the lower of which envelopes the two bony points of the opercle. The 

 posterior Hmb of the prffioperculimi very indistinctly crenulated. 

 Caudal very elongate and pointed, with the middle rays veiy broad ; 

 the second anal spine scarcely one-half the length of the first ray. 

 Coloration imifbrm ; in adult specimens a deep-black spot in the 

 axil, in yoimger ones a bluish-black spot on the upper half of the 

 operculum. 



Seas of Chusan, Pinang, Malayan Peninsula, Singapore, and 

 Borneo ; Tenasseiim coast. 



a, h. Two largo specimens : stufi"ed : not good state. From the Col- 

 lection of the Zoological Society. 



» Cuv.4 Val. V. pi. 140. figs. 3 & 4. 



