A SYNOPSIS OF CHARACTERS OF SOME FISHES 

 BELONGING TO THE ORDER HAPLOML 



EDWIN CHAPIN STARKS. 



The orders Haplomi and Iniomi are distinguished from the 

 Nemotognathi (the cat fishes) and the Plectospondyli (the min- 

 nows and suckers) by having normal anterior vertebrae ; from the 

 Isospondyli (the herring and trout-like fishes) by the absence 

 of a mesocoracoid ; from the several orders of eel-like fishes, by 

 the comparatively few vertebras, the presence of ventral fins, and 

 the unrestricted gill openings ; from several peculiar small orders 

 by apparently sufficient characters, but which for present pur- 

 poses need not be considered. 



Thus these orders seem to be made up of soft-rayed fishes, 

 which are thrown together because they lack the distinguishing 

 characters of other groups, rather than because they have such 

 characters of their own. This condition naturally would tend to 

 bring together forms that are not very closely related. 



The families of the Haplomi have either widely diverged from 

 each other or are not of the same line of descent. The order is 

 not held together by any important character, though some 

 very peculiar characters may be used to rather widely separate 

 three groups. 



I have not studied the Iniomi, 1 but from the definition given be- 

 low I find it impossible to separate the Haplomi from it. The free 

 condition of the scapular arch has been the most useful character 

 in separating these two orders, but as this condition is found 

 in the families Esocidae and Umbridae, it cannot be used unless we 

 transfer these families from the latter order to the former. Ob- 

 viously this is not advisable as Umbra, especially, is certainly 

 nearer the family Pceciliidae than it is to any family in the order 

 Iniomi. 



The Iniomi was established by Dr. Gill 2 to include those forms 



1 Except to determine that the condition of the attachment of the scapular arch to 

 the cranium is the same in Synodus as it is in Esox and Umbra. 



2 Proceedings of the U. S. National Museum, 1884, p. 350. 



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