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Part III. — Twenty -fourth Annual Report 



In respect to the Girth, a character in which there is a wide difference 

 existing among the three species, so far as the eye can judge, we find a 

 distinct enough separation between certain of the species. At the 

 pectoral region luscus has a girth equal on the average to 60 per cent, of 

 the length of the fish, thus exceeding by a considerable amount the 

 respective girth in minutus and esmarkii. And since the range of 

 variation in luscus does not overlap that of esmarkii the difference in the 

 girth is of some specific value. The ranges of variation in luscus and 

 minutus meet though they do not overlap, and between these two the 

 character is of more or less negative value. Minutus and esmarkii 

 overlap in their ranges of variation and this character is not therefore of 

 value. At the anus, the girths in the three species increase a little. The 

 girth of minutus now overlaps that of luscus. In the girth at the root of 

 the tail, where a considerable difference exists between minutus and 

 luscus, judging by the eye, a small difference only is shown by the per- 

 centages, but a complete separation is seen between luscus and esmarkii 

 in respect to this character. The dorso-ventral height of the body agrees 

 closely with the girth relations. 



In all three species the horizontal diameter of the eye is on the 

 average as great or greater than the length of the snout, i.e., the distance 

 from the tip of the jaws to the anterior edge of the orbit. Luscus 

 has a distinctly smaller eye than minutus and esmarkii — which two 

 agree exactly — but complete separation in this character does not 

 hold between any two of the species. In the size of the interorbital 

 space the reverse relation is seen, luscus having a larger average than the 

 other two, in which there is equality. By their variation, however, they 

 merge into one another. 



In the matter of the lengths of the ventral, pectoral, and first dorsal 

 fins, although very distinct agreements and differences are shown in the 

 averages, still the latter are so small that they are really of no specific 

 value. Thus in minutus and esmarkii the average size of the ventral fin 

 is the same, while that of luscus is a little larger ; whereas in the case of 

 the pectoral fin, luscus and esmarkii agree closely and have a fin a little 

 longer than minutus. The first dorsal fin is on the average rather larger 

 in luscus than in minutus, but the two ranges of variation overlap. 

 This character was not noted in esmarkii. 



In the following characters — height of the lateral line above the lateral 

 axis, the length of the rami of the tail, and the spread of the tail, the 

 greatest height of the unpaired fins — only a few observations were made. 



Luscus shows a considerably higher bend in the lateral line than 

 esmarkii, and a little higher than minutus. 



The lengths of the rami of the tail of the three forms agree closely, but 

 in the spread of the tail luscus and minutus exceed esmarkii, being on the 

 average half as broad again as the latter. 



The length of the barbel was in esmarkii on the average 3 per cent, of 

 the length of the fish ; in one specimen of minutus the barbel was 5 per 

 cent, of the same quantity. 



Distances from the Anterior Tip of the Body. — The average for the 

 length of the snout, i.e., the distance of the anterior border of the orbit 

 from the tip of the jaws, is the same in luscus and minutus, and 1 per 

 cent, over that in esmarkii ; but in the latter the snout is measured from 

 the tip of the mandible, which projects on the average 1 per cent, in front 

 of the premaxilla. When that amount is subtracted we get an equal 

 average measurement for the snout in all three. 



The ventral fin is situated nearest the tip of the jaws in luscus, next in 

 minutus, and farthest back in esmarkii. The ranges of variation of the 



