THICK-LIl'PKI) r,]{.\\ MUM.KT. 



335 



specimens of as great a length as (i().") nmi.. and ac- 

 cording to Dav the s|)('ci('s nia\' attain a leiigtli ot i) 

 dm. and a weight of (!"/'.t i<gui. The oi'iginal of our 

 tigiire is a smaller specimen, a female measuring >> dcm. 

 from tlie tip of the snout to the end of the middle 

 caudal rays, in -which oik' or two of tiic points most 

 characteristic of the spcicies ha\-e not yet become so 

 distinct as they sometimes do in other cases. In this 

 genus too, the signiticance of the changes of growth 

 represents the appearance of the specific differences; 

 and among the Scaudiuaxian species MufjU rlicJo oecn- 

 ])ies the highest raid< in the generic series of develo])- 

 ment. The character froin^ which the English name of 

 the species is derived, the tumidity of the upper lip, 

 which is usualh' so marked that the height of this lip 

 is considerably more than half the longitudinal dia- 

 meter of the eye (from about (JO to 70 % thereof), in 

 our specimen measures only 53 ?^ thereof or only slightly 

 more than it ma^' measure, thougli it be only in ex- 

 ceijtional cases, in full-grown specimens of Miigil cdji'ifo. 

 Similar changes of development in conjunction with 

 individual variations, render the species of this genus 

 extremely difficult to determine. Thus we tind in the 

 above list of synonyms that this species has borne the 

 name of all the three chief species of the genus. 



In its general appearance, apart from the structure 

 and ])osition of the fins, the Thick-lipped Gray Mullet, 

 like the two following species, reminds us of a broad- 

 backed Herring or (TWA'uiad; but the broad-topped, 

 slighth' convex and, for the most part, scaly head", 

 with the broad snout, at once gives the Gray Mullets 

 a distinctive feature. The colour is not unlike that of 

 the Herrinij, Ijcing- a briffht, irreenish steel-blue on the 



back'' and silvery on the bell\-, but marked with the 

 singular, longitudinal, blue streaks, seven or eight in 

 nund)er, on the sides of the body. Tlw^ gill-co\er is 

 of a bright golden lustre, which, in xoiing sjtecimens 

 at least, is visible through the scales. The pectoi'al 

 tins (scaly at the base) are pale and transparent, but 

 moi'e or less strongly tinged with yellow and with a 

 more or less distinct black spot at the upper |)art of 

 the base. The ventral Hns, like the belly, are milk- 

 white witli a silvery lustre. All the vei-tical fins are 

 more or less distinctly gra\ . At least the fir.st three 

 vay?, of the first dorsal tin are covered on the broader 

 side with small scales, and all the rays of this fin are 

 of the same colour as the back. The second dorsal fin 

 and the somewhat paler an;d fin (both covered with 

 small scales on the fin-membrane in front and at the 

 base at least), as well as the caudal fin (with more 

 numerous scales both on the fin-membrane and at the 

 base of the rays), are ashy blue, which is also the pre- 

 dominant colour of the iris, though it has an inner 

 i-ing of a golden colour next the pu])il, which is black. 

 The greater ))art of the upper lip is grayish blaek, but 

 inferiorly it grows paler and is white at the margin. 

 Such was the appearance of the young specimen which 

 Mr. ('. A. Hanssox forwarded to the Royal Museum 

 from Stronistad, immediately after its capture. 



The chief characteristics of the older specimens are 

 the comparativelv short head'', the lower (more elongated) 

 shape of the body'', the sometimes greater relative distance 

 between the tip of the snout and the first dorsal fin', the 

 somewhat shorter ventral fins-' and the somewhat shorter 

 base of the anal fin^, while the lower lobe of the caudal 

 fin seems to become shortei- and shorter than the upper. 



" Tlie breadtli (jf ttie head beliind (straiglil across tlie posteridr part (if tlie sill-cuver) is about --j "f its length. From this point 

 tlie body tapers evenly towards the caudal fin, the breadtli (thickness) at the beginning of the first dorsal fin being about equal to or slightly 

 greater than tlie least depth of tlie tail. 



'' Cf., however, the above remarks on tlie variations of colour lielonging to different localities. 



■■ In the specimens from Bohuslan behmging to the Royal Museum, between 207 and 416 mm. long, the relative length of the head 

 decreases witli increasing age from a.^^'l to 22 K of llie length of the body miivi:i the caudal fin, and the length of the head behind the eyes 

 decreases in tlie same manner from 12'2 to 11'6 °i of the latter length. 



'' The greatest depth of tlie body (at the beginning of the first dorsal fin) decreases in the manner just described from 21' ^ to 19' , 

 °i of the length of the body (from the tip of the snout to the end of llie middle caudal rays); and the length of tlie liead behind the eyes 

 thus increases from 51'7 to 54"8 "o of the greatest depth of the body. 



'' This distance increases, in the above specimens, from about 44 to about 45''.^ % of the length of the body or from about 69 to 

 about 7?j \ of the distance between tlie ana! fin and tlie tip of the snout, hut (iroves to be somewhat greater in the males than in the fe- 

 males. This change of growth is more distinctly shown in comparison with llie length of llie head, which decreases from 48 to 45 K of 

 llie distance between the first dorsal fin and tlic tip of the snout. 



■' The relative length of lliese fins diminishes in the above specimens from IS'S In 11 \ of the length of the body or from about 

 86' , to about 74 % of tlie length of the pectoral fins. 



:' The length of the base of this fin diminishes in tlie above specimens from lO'l to 8-8 ". of the length of the body or from 100 

 to about 90 \ of the least deptli of tlie tail. 



