68 



Aleuterius? brownii. Richardson. 



Aleuterius trossulus. Richardson. 



Radii:— D. 2]— 33; A.30; C. 11 ; P. 11. 

 (Bauer's drawing). 



Daring Captain Flinder's voyage of discovery round 

 Australia, Mr. Ferdinand Bauer made highly finished co- 

 loured drawings of fish which are now in the possession of 

 Dr. Robert Brown, and which this gentleman has kindly 

 permitted me repeatedly to examine. One of thera repre- 

 sents a very handsome species, having entirely the aspect of 

 a Monncanthus, except that there is no indication of the 

 protrusion of the point of the pelvic bone through the in- 

 tegument. In Monacanthus variabilis described above, 

 the rough point of the pelvic bone might, by a less correct 

 observer than Mr. Bauer, have been overlooked, as being 

 merely a part of the common scabrous surface, it is 

 conceivable that this point may be even less perceptible in 

 other species, and some doubt must therefore exist, until 

 the fish be again discovered, as to whether it ought to be 

 considered as a Monacanthus, having a minute tip to the 

 pelvic bone, or an Aleuterius, with the coarse coat and ex- 

 ternal aspect of a Monacanthus. The specific name is in- 

 tended as a small tribute of respect to the distinguished 

 naturalist, who laid the foundation of his fame by his re- 

 searches on the voyage on which this fish was discovered. 



The drawing is 12|- inches long, and represents an oval 

 fish, blunt in front without any projecting snout, and 

 the height contained rather more than thrice in the total 

 lengtli, caudal included. The integuments are covered 

 with lanceolate, apiculate spines or bristles, mixed with 

 much more minute asperities represented in a magnified 

 drawing of a portion of the skin. The sides of the tail are 

 also armed by four long, curved, cylindrical spines, placed 

 one pair over the other. The teeth, similar to those oi Mo- 

 nacanthus, are more conical and acute than usual, with deep 

 notches between the cusps. The dorsal spine is toothed 

 behind and before ; the anterior teeth ranged in two rows, 

 being shorter than those which arm the hinder edges of the 

 spine. The gill opening is oblique, and is eight-tenths of 

 an inch long. 



The ground tint of the fish is pistachio, or sap-green, 

 and azure-blue dots are scattered over the whole body. 

 The spots are replaced by blue lines on the top of the back 

 anteriorly, round the mouth, between the pectorals, on the 

 temples and under part of the cheek. The scaly fillets 

 along the bases of the dorsal and anal are blue, and there 

 is a blue line near to the anal, parallel to its base. Six 

 short blue bars radiate from the eye, and the nasal region 

 is spotted with blue. The side of the tail is a bright saf- 

 fron-yellow, shading off towards its middle into a rich 

 orange-brown. The four lateral spines of the tail are 

 placed in this orange patch, each having a green circle 

 round its base. The anal and dorsal fins and the rays of 

 the caudal are sap-green. The iris is prussian-blue, 

 encircled by yellow. 



Hab. Coasts of Austraha. 



Radii:— D. 1|— 28; A. 26; C. 12 ; P. 11. 

 Plate XL., fig. 5, natural size ; 6, magnified. 



This fish has the aspect of a Monacanthus, but if the 

 total concealment of the pelvic bone by the integuments 

 without any vestige of a protruding point be held, with 

 Cuvier, as the essential character of Aleuterius, it must be 

 ranked in this genus. 



It differs from the known species of Aleuteres in the 

 high and short form of the body. The highest part of the 

 profile is at the commencement of the second dorsal, fi-om 

 whence it descends to the mouth, with a curvature resem- 

 bling the italic y reversed. The abdomen hangs down like 

 a dewlap, but it is filled to the lowest point with the intes- 

 tines, and has no thin membranous edge, being as thick 

 before the anus as the back is. The height from the second 

 dorsal to the point of the pelvic bone is equal to the length 

 from the mouth to the tail. The dorsal spine stands over 

 the middle of the orbit, and is roundish, with the tips 

 scarcely pungent. Its height is not above one-fourth of 

 the extreme height of the body, and it is densely covered 

 with minute grains, which lengthen into very fine acicular 

 bristles near the membrane. There is no vestige of a trig- 

 ger ray to be detected externally. Both the dorsal spine 

 and pelvic bone are flexible in our specimen. The gill- 

 opening is exactly over the base of the pectoral. The skin 

 is densely covered with slender, flexible, acute bristles, 

 (fig. 6) which are so delicate as to give a velvety feel to the 

 finger. The colour of the specimen, which has been long 

 in spirits, is blackish-green, with some minute darker 

 specks and dots of a pale colour scattered over the body, 

 and most crowded on the face and flanks. Along the pel- 

 vic bone, and near the belly the dots run into streaks. The 

 rays of the caudal are also speckled with black, the other 

 colours are effaced. Length of specimen, 2j inches. 



Hab. Sea-coasts of Western Australia. 



Aleuterius ? baceri. Richardson. 



Radii :— D. 1 1 



-26 vel 27 ; A. 21 ; C. 9 : 

 (Bauer's drawing). 



P. 6 vel 7. 



This species is named in honour of Mr. Ferdinand 

 Bauer, being founded on one of his admirable drawings in 

 Dr. Brown's possession. The figure presents the careful 

 execution and felicity of touch which characterize Mr. 

 Bauer's pencil, and looking to his known scrupulous accu- 

 racy in details, it may be considered as the representation 

 of a generic form not yet described, in which the charac- 

 ters of several groups of Plectognathi are combined. It 

 exhibits the undivided dental plate of Diodon, the in- 

 flated body and dermal spines of Tetrodon, and the fins 

 of Aleuterius. We shall not venture upon the formation 

 of a new generic name without having seen a specimen of 

 the fish, and it is therefore placed provisionally in Aleute- 

 rius, with which, on the whole, it best agrees. 



