PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 31 



distinguished by its larger scales, which are arranged in 18 to 20 lateral 

 rows, iustead of 25 to 27, as in B. tyrannus. The generic relations of 

 this species were recognized many years ago by Professor Gill, and its 

 name should stand as Brevoortia pectinata. (Jenyns) Gill. 



A third species occurs in the Gulf of Mexico. It is distinguished by 

 its larger head and fins. It appears to have never been described, and 

 for this form the name Brevoortia patronus is proposed. It is accom- 

 panied by the same Crustacean parasite that is found in the mouths of 

 B. tyrannus, to which Latrobe gave the significant specific name of 

 prccgustator. 



Brevoortia tyrannus, (Latrobe) Goode. 



Diagnosis. — Head and jaws short, the length of the head less than 

 one-third of the length of the body, less the caudal fin, especially short 

 in var. aurea ; the maxillary in length much.less than three-twentieths 

 of the length of the body. Height of body about one-third of total 

 length, in very fat individuals three-eighths. Fins comparatively short, 

 the height of the dorsal less than length of maxillary, and considerably 

 less than three-tenths of length of body, that of the anal usually less 

 than half that of maxillary, that of ventral always less than one-tenth 

 of total length, the length of middle caudal rays one-fifth that of body 

 and less, that of exterior caudal rays usually about three-fourths, often 

 less than two-thirds, and rarely more than five-sixths of total length. 

 Fins all shorter in var. aurea. Insertion of ventral far behind tip of 

 pectoral. Insertion of dorsal about equidistant from snout and base 

 of middle caudal rays, but varying two or three one-hundredths to 

 either side of the median point, and always slightly behind the vertical 

 from insertion of ventrals. 



Scales of medium size, much serrated, arranged very irregularly in 

 24-2G transverse and GO-SO longitudinal rows. Scales forming sheath 

 at base of pectoral not large. Squamatiou of caudal lobes moderate. 



Operculum strongly striated in var. menhaden, almost smooth in var. 

 aurea. 



Scapular blotch conspicuous. 



This species is easily distinguished from Brevoortia patronus by its 

 shorter head and fins, by its slenderer body, and its pectinated scales, 

 and from B. pectinata by its smaller, less regularly arranged, and more 

 numerous scales, and its shorter, less furcate caudal fin. 



INDIVIDUAL VARIATIONS AND SPECIAL CHARACTERS. 



Head.— The length of the head varies from 0.28 to 0.33. The poste- 

 rioi end of the maxillary extends to a point in the vertical from the centre 

 of the orbit. The length of the skull, as indicated by the M distance 

 from snout to nape", varies from 0.19 to 0.23. The length of snout, 

 measured from a line drawn perpendicularly through- the centre of the 

 orbit, varies from 0.09 to 0.11. The length of maxillary varies from 



