160 CALIFORNIA ACADEMY OF SCIENCES 



In our smallest specimens, the belly is white, the back brown with small 

 white spots, one at the base of each spine; along lower margin of sides are light 

 spots of larger size, enclosed in a network of dusky lines. In slightly larger speci- 

 mens, the white spots on back have disappeared, and the under parts are covered 

 with a close black reticulum, the lines of which show a tendency to a lengthwise 

 arrangement. This tendency becomes dominant in specimens about 3 cm. long, 

 the lower parts then marked with parallel black lines of varying width and intensity, 

 which occasionally anastomose. The white dorsal spots soon reappear, and the length- 

 wise streaks begin to fade, wholly disappearing in adults. 



We have had for comparison numerous young and adult specimens from the 

 Hawaiian Islands, and two young individuals from Japan. No differences are discov- 

 erable, so we have been forced to conclude that T. hisjndus is identical with 

 T. erethizon, and is a species of universal distribution in the tropical Pacific. 



293. Eumycterias punctatissimus {Oilnther). 



Plate XXIII, Fig. 46. 



Not rare among the rocky islands in Panama Bay. 



The white spots are always numerous and crowded, especially on the lower 

 part of the sides, but they vary considerably in size, and the brown lines forming the 

 network enclosing them are sometimes wider, sometimes narrower. The belly is 

 always white. The sides and top of the head, the najie and the whole dorsal line, 

 are marked with numerous small blue spots, usually surrounded each by a darker 

 ring; the eye is occasionally, but very rarely, surrounded by blue radiating streaks. 

 Young specimens are sometimes marked by an obscurely ocellated dusky area below 

 the dorsal fin, but no trace of this persists in adults. The youngest specimen, 12 ram. 

 long, is a uniform warm brown, without trace of spots. The basal fourth of the 

 caudal fin is usually covered with fine white spots, the remainder of the caudal and 

 all the other fins, translucent, unmarked. 



The vertical fins are short, with evenly rounded margins. The pectorals are 

 strongly emarginate, with the upper lobe the longer. The dorsal and anal each 

 contains 9 rays (rarely 10). There is a short nasal tube widely open at the summit. 



Family DIODONTID^. 



294. Diodon holacanthus Linnceus. 



Three specimens were secured, 115, 179, and 280 mm. long. All show the 

 characteristic black cross-bars and blotches ascribed to this species. Round black 

 spots are also present on the lighter spaces of the back, and on the postocular area, 

 where they are largest. Small black spots are present on the snout in the two smaller 

 specimens, but are lacking in the larger one. In all of the specimens, large black 

 spots are present over the ventral region, one in the axil of each spine. They are 



