494 Survey of Fishing -Grnunds, West Coast of TrelanJ, 1890—1891. 



identity of the two species, in the absence of an enumeration of these proportions 

 in a series of examples extending over a considerable range of size. Om" Table 

 shows that, among specimens of the A. laterna type, the eye may be perceptibly 

 larger in the male at a length of only 8.3 cm. (c/. 5" and J), while on the other 

 hand no such sexual dimorphism maybe apparent in specimens slightly larger ((r), 

 and the eye may even be largest in individual females amongst the smaller fish 

 {cf M and K). The proportions of the eyes in N are of no value, since the 

 apjiarent smallness of these organs is obviously due to bad preservation. The 

 reduction in the relative length of the maxilla in the male may evidently manifest 

 itself in specimens of A. laterna of about 9 mm. {cf. i\ G, and H), and it may {H 

 and 0) or it may not {G) be accompanied by a corresponding sexual dimorphism 

 in the size of the eye. It will be noticed that, in the case of the eyes, there is a 

 greater sexual difference in the large specimens {A—D), including the males 

 conforming to A. lophotes than in any of the A. laterna type. This, as we think, 

 tends to support rather than to refute the correctness of Mr. Cunningham's views, 

 since a sexual dimorphism related to size would naturally become more pronounced 

 with the growth of the individual. We also believe that the evidence which our 

 Table affords of the occasional assumption of these features of sexual dimorphism 

 in small examples of A. laterna greatly strengthens the case for the identity of 

 the species. 



AjDart from the proportions of eyes and jaws, there is a discrepancy in the 

 observed number of the dorsal and anal rays in A. lophotes and A. laterna. The 

 value attached to even a considerable discrepancy in the case of forms in which 

 the fin-rays are very numerous must depend largely on individual opinion, but it 

 is certainly a matter which ought to be taken into account in an endeavour to 

 establish the existence of a single species. Mr. Cunningham, however, only 

 enumerates the formulae of one male exhibiting the A. lophotes characters, and one 

 large female, and of one female which, from its small size, was presumably 

 typical of A. laterna. It so happens that the formula of the last-named examjDle is 

 considerably less than that of the other two, and is, in fact, illustrative of the 

 discrepancy indicated by the observations of earlier writers. 



In endeavouring to throw fresh light on the subject, we have counted the rays 

 in a number of our own specimens, and have also collected the information available 

 in existing literature. 



The results are given in the following Table : — 



