PEOCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 59 



The greatest leugtli of the head (.37) slightl;^' exceeds the distauce of 

 the spinous dorsal from the snout (.36). The length of the postoeular 

 depression (.11) equals more than 3 times the length of the snout (.03^), 

 and is contained about 9 times in the total length. The width of this 

 depression (.07^) equals about f of its length. The greatest width of 

 the head (.28) equals 4 times the length of the second dorsal spine (.07). 

 The jaws are shorter than in A. anoj>lus. The length of the upper (.15^) 

 equals half the length of the anal base (.31), and is contained 6.J times 

 in the total length (less than 6 times in A. anoplus). The length of the 

 mandible (.21) is contained ^ times in the total length. The maxilla 

 extends to a peri)endicular, drawn at a distance behind the eye equal to 

 the short diameter of the eye, and the mandible ends in the same ver- 

 tical. The long diameter of the eye (.03) equals half the length of the 

 last ray of the second dorsal (.00). 



The distance of the spinous dorsal from the snout (.36) is a little less 

 than the greatest length of the head (.37). The length of its base (.11) 

 is contained 9 times in the total length, and equals the length of the 

 postoeular depression. The spines are all longer than in A. anoplus. 

 The length of the first (.07^) is nearly -J the length of the upper jaw, and 

 slightly exceeds that of the second (.07), which equals ^ of the length of 

 the mandible. The last spine (.02 J) is ^ as long as the first. The length 

 of the base of the second dorsal (.30) is contained 3 J tunes in the total 

 length, and equals 3 times the distance between the eyes. Its longest 

 ray (.19i) equals somewhat more than half the length of the head (much 

 less than half in A. anoplus). The length of the last ray (.06) equals the 

 distance from the snout to the orbit (.06). 



The distance of the anal from the snout (.57) equals nearly 3 times the 

 length of the longest dorsal ray. Its length of base (.31) is almost equal 

 to that of the second dorsal. The first ray (.04) is Iftilf as long as the 

 last (.08); the longest (.14i) is contained nearly 4 times in the ditstance 

 from the snout to the origin of the anal, and nearly 7 times in the total 

 length. 



The length of the middle caudal rays (.25) equals ^ of the total length. 

 The length of the external rays (.23) equals that of the ventral (.23). 



The distance of the pectoral from the snout (.35i) equals 5 times the 

 length of the second dorsal spine. Its length (.30i) equals 5 times that 

 of the last dorsal ra^^ It extends to the fourth anal ray. 



The distance of the ventral from the snout (.24) does not greatly ex- 

 ceed its length (.23), and is equal to the height of the body at the ven- 

 trals (.24). The ventral extends to about the origin of the spinous dor- 

 sal. The vent is under the anterior rays of the second dorsal. 



Eadial formula: B. VI; D. IV, 14; A. 13; P. 19-20; V. 6. L. lat. 

 ca. 80. 



Color. — Astroscopns ygrwcum has, on the upper parts, numerous 

 white spots, some of which are as long as the short diameter of the eye. 



Note. — In the tables of measurements the unit of length is the length 

 of body to the origin of the middle caudal rays. 



