126 



Part III. — Twenty-fourth Annual Report 



The extensive overlapping between luscus and minutus and between 

 minutus and esmarkii renders this character of value only as a distin- 

 guishing feature between luscus and esmarkii. In luscus the first anal is 

 always more than twice as long as the second anal; in esmarkii it is 

 usually less than twice the length of the second anal. 



The above is the most promising relationship between the lengths of 

 the fin-bases in any of the species. 



The three species agree fairly closely in the lengths of the dorsal fins, 

 but show wide diversity in the lengths of the anal fins. If we add the 

 bases of the fins of each species together, keeping the dorsal and anal 

 groups separate, the relations will be seen more easily. 





Sum of Bases 



Sum of Bases 



Species. 



of Dorsal Fins 



of Anal Fins 



(Average Sizes). 



(Average Sizes). 



G. luscus, 



49-3 



54-8 



G. minutus, . . 



50-7 



46-5 



G. esmarkii, 



50-5 



44-4 



In each species a portion of the dorsal edge equal to half the length of 

 the fish bears fin-rays. On the anal edge the size of the fin-bearing part 

 varies with the species. 



The Number of Rays in the Unpaired Fins. 



In the accompanying Table are arranged the average, maximum and 

 minimum number of rays found for each fin. A detailed analysis of the 

 numbers of fin-rays in each fish is given in Tables I, II, III. The range 

 of variation in each species is shown in Table V. 



Species. 



1 D. 



2 D. 



3 D. 



1 A. 



2 A. 



Max. 



Av. 



Min. 



Max. 



At 



Min. 



Max. 



Av. 



Min. 



Max. 



Av. 



Min. 



Max. 



Av. 



Min. 



G. luscus 



15 



135 



12 



26 



33 



21 



22 



30 



18 



36 



34 



31 



22 



31 



18 



G. minutus. 



15 



13 



11 



26 



33 



20 



23 



31 



19 



31 



38 



26 



23 



33 



20 



G. esmarkii. 



18 



15 



14 



29 



35 



21 



29 



3C 



23 



32 



39 



24 



30 



3: 



24 



In respect of the first dorsal, luscus and minutus agree closely both 

 in average, 13, and in the range of variation, 15-11. Esmarkii has & 

 larger number of rays, viz., 15 on the average, with a maximum and 

 minimum of 18 and 15 rays respectively. 



In the second dorsal the two former species are again almost identical 

 with an average of 23, while esmarkii has an average of 25. 



The close agreement persists between luscus and minutus in the 

 third dorsal also, esmarkii having in this fin also a higher average. 



The first anal, however, brings about a separation between luscus and 

 minutus; this was, of course, apparent also when the length of the fin- 

 bases were discussed. Luscus has 34 fin -rays, and minutus 28 rays in 

 the fin, while esmarkii approaches the latter closely, having an average 

 of 29. 



