FISH. 81 



exactly five times : height of the head at the nape two-thirds its own length. Mouth chevron- 

 formed, with a tubercle at the extremity of the lower jaw : lips thin. Some extremely minute teeth 

 in the jaws, but none on the palate or tongue. Suborbital obliquely truncated at the posterior 

 angle, but not dilated towards the extremity; the lower or anterior margin straight, and scarcely 

 if at all denticulated : the maxillary slender, not longer than the suborbital, and concealed beneath 

 it when the mouth is closed. The eye has an adipose veil covering a large portion of the iris : 

 diameter of the orbit one-fourth the length of the head : distance from the eye to the end of the 

 snout, equalling only three-fourths of the diameter. Orifices of the nostrils widely separate. 

 Number of scales in a longitudinal row about thirty-five; perhaps one or two more: in the 

 depth about twelve. Fourth dorsal spine very weak. A large triangular scale above the pec- 

 torals 5 the same also above the ventrals ; this last, which is the longer of the two, equalling one- 

 fourth the length of the fin. 



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



Length 11 inches 3 lines. 



Colour.—" Back coloured like Labrador felspar : iris coppery." — D. The dried specimen shows 



traces of about twelve longitudinal lines similar to those of many other species. 

 A second specimen exactly resembles the above, except in being smaller, measuring barely eight 



inches, and in shewing rather more trace of denticulations on the suborbital. 

 Habitat, Bahia Blanca and Monte Video. 



Tins species, which has the general characters of the 31. Cephalus of the 

 European seas, is probably the M. liza of Cuvier and Valenciennes ; but the 

 specimens are in a bad state of preservation, and some of the characters cannot 

 be accurately ascertained. The depth of the body appears to have been rather 

 greater than what is mentioned in the " Histoire des Poissons:" there is also some 

 appearance of small scales on the second dorsal and anal, which, according to 

 Cuvier and Valenciennes, is the distinguishing characteristic of their next species, 

 the M. curema; but it will not agree with this last in its other details. 



The larger of the above specimens was taken at Bahia Blanca, where 

 Mr. Darwin's notes state that it is plentiful ; the smaller one at Monte Video. 



2. Mugil ? 



Mr. Darwin's collection contains a second species of this genus from the 

 Keeling Islands, which does not appear to be identical with any of those 

 described by Cuvier and Valenciennes ; but as there is but one specimen, in a 

 very bad state of preservation, and the species inhabiting the Indian Ocean are 

 very numerous, as well as extremely similar to each other, I refrain from 

 describing and naming it as certainly new. I shall therefore merely point out 

 some of its leading characters, so far as they can be ascertained ; in the hope 

 that they may prove of use in leading others to identify it who may visit the above 

 Islands hereafter. 



