82 ZOOLOGY OF THE VOYAGE OF THE BEAGLE. 



Form and appearance of the mouth similar to that of the M. labeo of the Mediterranean. Lips 

 fleshy, and very much developed, with the borders fringed ; the lower one partially reflexed. 

 Apparently no trace of teeth anywhere. Suborbital with a shallow notch on its anterior mar- 

 gin, obliquely truncated at its posterior angle, and obsoletely denticulated. Maxillary slender 

 and slightly bent, nearly concealed beneath the suborbital, but showing a little beneath it, from 

 its being a trifle longer. The head is a little less than one-fifth of the entire length : the snout 

 short, and rather obtuse. Longitudinal diameter of the eye contained three and a-half times in 

 the length of the head : no appearance of any adipose veil. Orifices of the nostril approximat- 

 ing. The depth of the body cannot be accurately ascertained, but it appears to have been about 

 one-fifth of the entire length. The commencement of the anal is but very little in advance of that 

 of the second dorsal ; both fins appear to have been covered with small scales. Pectorals not 

 quite so long as the head : apparently no elongated scale above them : one, however, above the 

 ventrals, half the length of those fins. The fin-ray formula is as follows : — 



D. 4—1/8; A. 3/9; C, 14; P. 16; V. 1/5. 



The length of this fish is eight inches. 



Dajaus Diemensis. Richards. 



Dajaus Diemensis, Richards, in Proceed, of Zool. Soc. 1840, p. 25. 



This genus, which was established by Cuvier and Valenciennes, differs from 

 Mugil principally in having vomerine and palatine teeth : the snout also is rather 

 more produced, and the mouth less chevron-formed. There is but one species 

 described in the " Histoire des Poisssons," which is found in fresh water in the 

 Caribbee Islands. Dr. Richardson has briefly noticed a second from Van 

 Diemen's Land, in his recent description of a collection of fishes from that 

 country, in the " Proceedings of the Zoological Society." Mr. Darwin's collection 

 contains a specimen of this genus from King George's Sound, which, having 

 reason to think it might be the same as that described by Dr. Richardson, I sent 

 to this latter gentleman, requesting him to compare them. This he obligingly 

 did, and informed me in his answer that he could detect no differences between 

 them, beyond what might be the result of the different manner in which they 

 were preserved, his own specimens being in spirits, and Mr. Darwin's dried. 



I forbear giving a detailed description of this species, as one by Dr. Richard- 

 son will appear shortly in the Transactions of the Zoological Society ; and Mr. 

 Darwin's specimen is in such a bad state of preservation, as hardly to admit of an 

 accurate description of it being taken. I may just allude, however, to some of its 

 more striking peculiarities. 

 It appears to differ from the D. monticola of Cuvier and Valenciennes in having the teeth in the 



lower jaw, if they really exist, so minute and thinly scattered as to be scarcely perceptible 



those in the upper jaw, however, are very distinct; so likewise are the vomerine and palatine bands. 



There are also some very obvious teeth on the tip, and at the sides of the tongue, though few in 



