6 CALIFOUNIA ACADKMY OF SrlKNCre 



Tlic Pjiii:iiii;i specimens agree will willi llic niii;in;il ilcscri|ilii)ii nl' llic spccii's, 

 exri'pl ill tiio follosviiij:; ri'spci-ts: — 



((() DistniK'o I'roiu iiisi-rtioii of lirsl dorsal lo aiidiior iunt nl pectoral '; (not 

 "alxnil .\ ") its tlistanee from lip of snout. Tliis tliscrepaiicy is due, however, to 

 an error in tlie original description. Mr. Hartoii A. I'ean has Icindly re-examined 

 the tvpe, and slates tliat tlie lirsl distance is contained ahonl '2t times in the second. 



(b) Distance hetween dorsals 'J:\ to 2A times (not "2ii limes") base of lirst, 

 and 25 to 3i times ("a little more than :) limes") base of second. Mr. Bean 

 gives base of lirst dorsal 2ii and base of second doisal ■]\, in the interspace hi Iween 

 dorsals. This interval is therefore longer in the type than in any of the Tanama 

 specimens. The latter agree, however, with the Ma/.allan specimens above menlioiied. 



A specimen of .1/. luiiiilalH>< in tlie United States National ISfiiseum (No. 

 46838), taken by the "Albatro.ss" at the moulh of the .\riileg(' Iviver, (iiilf of Cali- 

 fornia, has the proportions of the ty[)e. The base of the first dorsal, excluding the 

 tleshv hump which ju'ecedes the rays, is contained 2ii limes in the interval between 

 dorsals, the base of the second dorsal 'S-j times in this interval. It is evident, 

 therefore, that the size and relative positions of the dorsal lins niu>l be used with 

 caution for specific distinction. 



((■) Middle of dor.sal base usually midway between axil of pectorals and 

 anterior insertion of ventrals, sometimes very slightly nearer pectorals. In none of 

 the Panama siiecimens is it nearer the base of the pectorals by a distance equaling 

 the diameter of the eye, as given in the description of thi; type (slightly less than 

 this in the type according to Mr. Bean). 



Following are dimensions of a Panama specimen: — 



tntn. 



Total lensrtli 5:?o 



Length of head 95 



Length of snout » 4.^ 



Diameter of orbit '7 



Length of spiracle ."^-S 



Length of middle gill-slit '4 



Distance from tip of snout to front of mouth 34.5 



Distance from tip of snout to inner angle of nostrils 27 



Distance between nostrils 14 



Distance between angles of mouth 28 



Distance from tip of mandible lo line joining posterior angles of lijjs 21 



E.xtreme length of upjier lip 5-5 



E.xtreme length of lower lip ■'^ 



Distance from tij) of .snout to base of pectorals 113 



(ireatest width of pectoral base 23 



Outer pectoral margin 7' 



Inner |)ectoral margin 40 



Distal pectoral margin 57 



Axil of [xrctoral to base of ventrals 107 



Snout to base of ventrals 230 



Outer edge of ventrals 40 



