49 



mens, are detached, having a triangular piece of mem- 

 brane, as is represented in the figure, but in the recent 

 fish the membrane may have been continuous. The last 

 ray of the soft part of the fin has its posterior branch ta- 

 pering out into a fine point. The anal is similar in form 

 to the jointed part of the dorsal. Its spines are slender, 

 graduated, and comparatively short. The caudal is forked, 

 with acute tips. Its middle rays are much branched to 

 the base. 



The whole fish appears to have had considerable silvery 

 lustre, with little or no colour on the inferior parts, but with 

 a bluish or grey tinge above the lateral line, reticulated, 

 perhaps, by the paler edges of the scales. T?here are no 

 remains of spots, or other markings, either on the head, 

 body, or fins, except that the membrane between the limbs 

 of the lower jaw lias a sooty colour, 



Length of one specimen, lOj inches ; of the other, 

 fourteen. 



Hab. West Australia. 



Synbranchus gdtturalis. Richardson. 



Ch. Spec. S. cylindricus, caudd compressa attenuatd ; 

 colore hepatico-hrunneo subtus paulo dilutiore, facie 

 gutiureque griseis, brunneo marmoratis ; dentibus 

 acerosis. 



Radii ; 



■C. 7. 



Plate XXX., figs. 14—17. 



This small fish evidently appertains to the genus Syn- 

 branchus of Bloch, and Cuvier's Regne Animal (ii. p. .364). 

 It is truly monopterigian, a few rays being perceptible in 

 the caudal only, while the anal and dorsal are merely 

 low, cutaneous seams, or, as Cuvier says, adipose fins. 

 The Dondoo-paum of Russell, pi. 85, wants even these 

 seams, and has a still more tapering tail. It is further 

 distinguished by being universally black, and the furrows 

 of the lateral line, if they actually exist, are not shown 

 in the figure. The Unibranc/iaperiiira cuchia of Bu- 

 chanan-Hamilton (p. 16 and 363, pi. 16, fig. 4) is dotted all 

 over with black, and is marked on the shoulders and pec- 

 toral regions of each side, by three pale lines of difi'erent 

 lengths. A fish so coloured can scarcely be the same with 

 the uniformly black one of Russell, and indeed there is a 

 well marked difference in their forms, as represented in 

 the plates we have quoted, yet if there be not an error in 

 the pointing of a paragraph in the Regne Animal (ii. p. 3-54, 

 foot-note 2), Cuvier considers both these figures as being 

 referrible to the Synbranchus immaculatus of Bloch. In 

 his characters of the genus, he states the teeth to be ob- 

 tuse, but in our species the teeth are decidedly acute, and 

 under a lens appear subulate. They are disposed in a 

 single row on tlie limbs of the jaws, but crowded together 

 for some breadth on the tip of the lower one, and being 

 continued from the limbs of the lower one, along the tip 

 of the upper jaw, they become parallel and almost con- 

 tiguous, and in that form run forwards for a short space. 

 This kind of dentition is similar to what is represented in 

 the 'Calcutta Journal of Natural History' (iv. p. 411, 

 a.d. 1844), by J. McClelland, Esq., in his account of a 



Chinese species, named by him Pneumabranchus cinereus. 

 In that the palatine teeth are in a single row, but in ours 

 they form two or more rows; The species are further dis- 

 tinguished by their colour, and by the Chinese one having 

 the membranous edge of the tail, or the adipose dorsal, not 

 extending so far forwards. 



Synbranchus gutturalis is slender and cylindrical from 

 the head to the anus, it then becomes sensibly compressed, 

 and gradually terminates in a thin tapering tail, almost 

 filiform at the tip. The head swells out a little, the snout 

 is depressed and obtuse, being terminated by a thicki.sh, 

 reverted lip, which projects very sliglitly beyond the lower 

 jaw, also obtuse, and edged by a thick lip. Tlie mouth is 

 cleft more than half its length beyond the small eye. The 

 posterior aperture of the nostrils is immediately above the 

 middle of the eye, and the anterior one, which is smaller, 

 is over the inner angle of the eye, but it is not easy to dis- 

 tinguish the nostril of so small a fish from some pores on 

 the snout. None of the openings have tubular margins. 



A transverse slit on the throat, without a septum, and 

 distant nearly an eleventh part of the whole length of the 

 fish from the snout, is the only branchial opening. Its 

 hinder edge is smooth and even with the adjoining integu- 

 ment. The thin gill-membranes, united evenly in the 

 middle, form the anterior lip of the opening, and are tra- 

 versed longitudinally by nine furrows. Their rays cannot 

 be traced without dissection. 



A deep even furrow marks out the lateral line at the 

 middle of the height, and there is a fainter mesial furrow 

 on the top of the fore part of the back, extending to the 

 hind head, both being the effect of the swelling of the 

 muscles. The anus is less than a third of the whole 

 length distant fi'om the tip of the tail. 



The dorsal is a mere skinny hem, without rays, com- 

 mencing about midway between the gill-opening and anus, 

 at first very low, but rising a little as the tail becomes 

 more slender, and reaching to the extremity of the caudal 

 rays. The anal, beginning close to the anus, is similar to 

 the dorsal, and also reaches to the end of the caudal. lu 

 the caudal fin, seven unbranched jointed rays can be per- 

 ceived with the aid of a lens. There is not the slightest 

 vestige of pectorals. 



In colour the fish is uniformly liver-brown, slightlj- 

 paler along the ventral line, and darker towards the tip of 

 the tail. The throat and cheeks, with the snout, are bluish- 

 grey, mottled thickly with brown spots and lines. I have 

 been unable to detect scales with a lens, but very minute 

 ones may nevertheless exist, as^ Mr. McClelland states 

 that his China species is covered with minute scales. This 

 fish being, if we may judge from the figure, 13|^ inches 

 long, may be expected to show the scales more distinctly 

 than our small one, which is little more than a third of that 

 length. 



DIMENSIONS. 



Length from end of snout to tip of tail 5-22 incLes. 



„ „ anus 3-60 „ 



dorsal fin 2 85 „ 



„ „ gill-opening 0'60 „ 



Length of cleft of mouth 0-14 „ 



Distance between anus and tip of tail 1'58 „ 



Hab. Dampier's Archipelago. 



H 



