NOTES ON SOME PROBLEMS OF ADAPTATION : 4. THE 

 PHOTIC SENSITIVITY OF OGILBIA. 1 



W. J. CROZIER, 

 ZOOLOGICAL LABORATORY, RUTGERS COLLEGE. 



Parker ('09) has commented upon the curious fact that al- 

 though so primitive a chordate as ammocoetes exhibits a well- 

 defined integumentary sensitivity toward light, marine fishes as 

 a class seem devoid of this type of irritability, which is also 

 absent in Amphioxus (Parker, '08; Crozier, '17). Recently 

 Jordan ('17) has described the first recognized instance of photic 

 sensitivity resident in the skin of a marine teleost, the hamlet 

 (Epinephelus striatus}. I wish now to record a second example 

 of this type of sensitivity in a marine fish, Ogilbia (Brosmo- 

 phycis) verrillii Gar man. 



The case of Ogilbia is of peculiar interest. The Brotulidae, 

 to which group Ogilbia belongs, are for the most part deep water 

 fishes, but include several forms occurring in warm shallow 

 situations on the Pacific and on the Atlantic shores of America. 

 They seem to represent the ancestral type from which may be 

 traced the evolution of the blind brotulids of the Cuban caves 

 (Eigenmann, '09). The behavior of Ogilbia, concerning which 

 very little has been known, should in consequence be a source of 

 important information bearing upon the derivation of the related 

 cave forms. 



Ogilbia verrillii (Garman, 'oo) was first collected at Bermuda 

 by Verrill. According to Eigenmann ('09, p. 187) -who, curi- 



FIG. i. Ogilbia verrillii Garm. (X 25). Note the relatively minute eye. 



1 Contributions from the Bermuda Biological Station for Research, No. 130. 



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