LIFE-HISTORY OF AMPHIGONOPTERUS AURORA. I 85 



occasionally leaping clear of the water (a habit observed only at 

 Pt. Purisima, California, on August 13). During high-tide, how- 

 ever, they must seek the protection of crevices in the sides of the 

 pools, for otherwise they would be dashed about on the rocks by 

 the pounding, churning surf as it breaks on the reefs. In corre- 

 lation with its preference for pools clearer of vegetation, and 

 with its habits of swimming about rather more freely, Amphi- 

 gonopterus aurora- is more extensively silvery than Micrometrus 

 minimus, and lacks the dark color pattern characteristic of that 

 species 2 (see Fig. i). In this connection we should recall that 

 practically all free-swimming or pelagic fishes are silvery and 

 lack the dark markings usually developed in fishes which live 

 among rocks or plants. 



Like most reef-fishes examined, Amphigonopterus aurora is 

 not heavily parasitized, a fact apparently correlated with the 

 strength of the wave and tidal currents on the reefs. Occasion- 

 ally, however, a slender lernsean copepod was found attached to 

 the inner surface of the base o>f the pectoral fin, or to the anal fin 

 near its base. 



BREEDING SEASON. 



The breeding season of Amphigonopterus aurora is the sum- 

 mer, approximately synchronous with that of Cymatogaster ag- 

 gregatus, which breeds in bays and estuaries. It begins shortly 

 before the first of June, as is evident from the observations made 

 on the reefs of Piedras Blancas, California, during the first week 

 of that month. Most of the many females taken on that occasion 

 contained young, relatively few of the largest being spent. Fur- 

 thermore, all of the hundreds of young in the higher pools were 

 approximately of the size at which they are born. The breeding 



judging from the approximate number of the fishes of each size. In a number 

 of pools fished during the summer and fall, the young of the year of each 

 sex were so uniform in size that it seemed probable that they had remained in 

 that pool together since their birth at some time during the breeding season. 



2 The most conspicuous color feature of Amphigonopterus aurora (the one 

 on which its specific name was based) is the longitudinal band of golden or 

 orange color, which is rarely obsolete (a row of blotches of similar color and 

 position often is present in M. minimus, representing this longitudinal band 

 of A. aurora). In young specimens the vertical fins are dusky with a reddish 

 tinge, the spinous dorsal, and in the male the anterior portion of the anal fin, 

 being darkest ; the pectoral, nearly colorless. 



