6 CALIFORNIA ACADEMY OF SCIENCES 



The Panama specimens agree well with the original description of the species, 

 except in the following respects: — 



(a) Distance from insertion of first dorsal to anterior root of pectoral j (not 

 "about 3") its distance from tip of snout. This discrepancy is due, however, to 

 an error in the original description. Mr. Barton A. Bean has kindly re-examined 

 the type, and states that the first distance is contained about 2| times in the second. 



{b) Distance between dorsals 23 to 2* times (not " 2f times") base of first, 

 and 23 to Sh times ("a little more than 3 times") base of second. Mr. Bean 

 gives base of first dorsal 21 and base of second dorsal 3i, in the interspace between 

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

 specimens. The latter agree, however, with the Mazatlan specimens above mentioned. 



A specimen of J/. Innulatus in the United States National Museum (No. 

 46838), taken by the "Albatross" at the mouth of the Mulege River, Gulf of Cali- 

 fornia, has the proportions of the type. The base of the first dorsal, excluding the 

 fleshy hump which precedes the rays, is contained % times in the interval between 

 dorsals, the base of the second dorsal 32 times in this interval. It is evident, 

 therefore, that the size and relative positious of the dorsal fins must be used with 

 caution for specific distinction. 



(c) Middle of dorsal base usually midway between axil of 2)ectorals and 

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

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

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

 this in the type according to Mr. Bean). 



Following are dimensions of a Panama specimen: — 



mm. 



Total length 53° 



Length of head 95 



Length of snout 43 



Diameter of orbit ' 7 



Length of spiracle 3-5 



Length of middle gill-.slit 14 



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 to line joining posterior angles of lip.s 21 



Extreme length of upper lip 5-5 



E.xtreme length of lower lip S 



Distance from tip of snout to base of pectorals 113 



Greatest width of pectoral base 23 



Outer pectoral margin 7' 



I nner pectoral margin 40 



Distal pectoral margin 57 



A-xil of pectoral to base of ventrals 107 



Snout to base of ventrals 230 



Outer edge of ventrals 40 



