31 



scaleless, as are also the corner of the cheek next the 

 mouth, the lower limb of the preoperculum, the interoper- 

 culum, fore part of the siiboperculum, and all the jaws. 

 The scales on the top of the head are small, and run for- 

 ward to the posterior nostrils. The scaly cheek is level 

 with the upper limb of the preoperculum, and the scales 

 become minute inferiorly, and terniinat(! very unevenly. 

 The limbs of the preoperculum are entire. The operculum 

 ends in an obtuse flat point, beyond which the membranous 

 lobe of the inleroperculum extends. A wide shallow notch 

 slopes forwards above the opercular point, having its ante- 

 rior corner also rounded. The form of the entire gill- 

 cover is triangular, with a bluntish tip. The gill-mem- 

 branes are united beneath, and are supported by six rays 

 on each side. 



The scales of the body in situ show concentric folds of 

 cuticle, and have strongly toothed edges. The lateral line 

 is traced in the upper third of the height, and is nearly 

 straight, or very slightly arched. It is formed by a simple 

 tube on each scale, which, when the specimen is removed 

 from the spirits, speedily shrinks into a narrow furrow. 

 There are fifty-eight scales in the lateral line. A line of 

 similar tubes or furrovrs is continued forwards from the 

 lateral line along the temples to the eye, and there are, 

 as in Mufjil macrolepidotus, eight tubiferous scales on the 

 cranium, whose arrangement is shown in fig. 2, Plate XX. 

 A series of pores also exists along each limb of the lower 

 jaw, and round the edges of the preopercula. Small scales 

 are densely tiled on the lower half of the caudal, and on 

 one-third of the pectoral. A clear streak coincides with 

 each row of scales on the body, as in the mullets. 



The ventrals are attached under the middle of the sub- 

 operculum, before the pectorals. The form of the pectoral 

 is triangular, the fifth and sixth rays being the longest, 

 and the superior ones closely incumbent. The tip of the 

 fin, when turned back, reaches to the eighth dorsal ray, or 

 sixth anal one. The caudal is slightly crescentic at the 

 end. 



The specimens in the collection are numerous, and vary 

 in length from five to fourteen inches. 



Hab. The Falkland Islands. 



Plotosus miceoceps. Richardson. 



Ch. Spec. PI. pallide gidtatus marmoratusqtie, macula 

 uhloin/d supra pinuam pcctoialpiH ; capite octavam par- 

 tiin loiKjHudinis iotiiis ccqiianti. 



Radii :— D. 1 16— 92 ; A. 8G ; C. 8 ; (= 186) ; P. 1 19 ; V. 9. 



Plate XXL, figs. 4, 5, natural size ; figs. 6, 7, magnified. 



This Plotosus, for which we are indebted to the industry 

 of Mr. Bynoe, is remarkable for the smallness of its head, 

 which does not exceed the eighth part of the entire length 

 of the fish. The breadth of the head is superior to its 

 height at the nape, and about one quarter shorter than its 

 length to the gill-opening. The body is highest near the 

 middle of its length, and there its thickness is only half 

 its height. The tapering from thence to the acute point of 

 the tail is gradual. The moulh is of moderate size, the 

 lips thickish and granulated, especially the lower one. 



where the soft grains are in distinct rows, two in the middle 

 and three or four laterally. The teeth on the jaws arc 

 conical, with the tips truncated, and stand in three rows, 

 of which the outer row is tallest. There is a narrow tooth- 

 less space at the symphysis of the lower jaw, but in the 

 upper one the dental plates are contiguous. The vela are 

 very narrow, delicate, and waved or crenated on the edge. 

 The teeth on the vomer are in five or six rows, more worn 

 generally than those on the jaws, and the middle ones are 

 the highest. 



The barbels are in four pairs, the nasal ones being the 

 longest, and reaching beyond the middle of the jieclorals. 

 The maxillary barbels next in length reach to th(; gill- 

 opening. The barbels of the lower jaw are shorter, par- 

 ticularly the interior pair. The posterior nostril on the 

 base of the barbel could alone be made out, the anterior 

 one being imperceptible. 



The top of the head is studded with pores, whose tumid 

 lips form little round, soft grains. The lateral line is 

 straight and fine, but very conspicuous, and is formed of a 

 chain of small pores or tubes raised above the surface. 

 There is no perforation in the integuments of the axilla of 

 the pectoral. The specimen has the genital papilla and 

 cauliflower-like appendage usual in the genus. 



The rays of the fins are enveloped in thick membrane, 

 and were reckoned with difficulty. The spines of the 

 pectoral and first dorsal are shorter than the soft rays, and 

 are serrated, the ])ectoral si^ine on one side only, the dorsal 

 one on both. They are enveloped in skin, but pierce it 

 when handled (figs. 6, 7). The first dorsal is tall, and 

 tapers to a filamentous point. 



In spirits the specimen has a light brownish or yellowish- 

 grey tint, thickly mottled, fins included, with round 

 spots and indefinite blotches of pale lead-grey. There is 

 an oblong mark on the side above the pectoral. 



The liver of our specimen had perished, but the recesses 

 on each side of the first vertebra for the reception of its 

 upper lobes exist. The peritoneum has a silvery lustre. 

 The gut, small for the size of the fish, is gathered in folds 

 round the margin of the mesentery, and becomes gradually 

 of less caliber from the oesophagus to near the anus. Its 

 upper end was blackish, having been probably stained by 

 the food. A small quantity of very soft %vell-digested 

 matter was contained in the intestinal canal. 



DIMENSIONS. 



Length of the specimen 9"20 inches. 



„ fiom snout to anus 'l-bd „ 



Hab. North-west coast of Australia. 



Plotosus megastomus. Richardson. 



Ch. Spec. PI. fuscus, obscure parciterque guttat us ; capite 

 quartam partem longitudinis iotius efficiente, ore la.vo, 

 cirrhis decent. 



Radii : — Br. 11 ; D. 1|4— 82 ; C. 16 ; A. 76. (= 174) ; 

 P. l|y; V. 11. 



Plate XXI., figs. 1, 2, 3, half the natural size. 



The difference of aspect between this fish and other Plo- 

 iosi arises chiefly from the length of the head, and the large- 



