14 U.S. NATIONAL MUSEUM BULLETIN 282 



Ictaluridae, pore Nl is close to the anterior naris and the midnasal 

 (N2) is in a slightly posteromedial position. Connection of this system 

 anteriorly with the infraorbital system is infrequent. However, in 

 three species of Noturus (lachneri, exilis, and miurus) and in SaUm 

 eurystomus the connection is typical. In these, the midnasal (N2) 

 and "mediad lacrymal" (Ll) pores fuse to form an "internasal pore" 

 (pi. 1, fig. 1); i.e., topographically the pores involved in fusion lie 

 between the anterior and posterior nares. 



Posteriorly the lateral cephalic canal connects with the lateral 

 body canal after passing through the upper end of the supraclei thrum. 

 The posterior extent of the lateral line varies considerably between 

 species. It ends just behind the head in Noturus, beneath the dorsal 

 fin in some Ictalurus, and extends to the base of the caudal fin in other 

 Ictalurus. 



Relationships of the Genera of the Ictaluridae 



During the course of the revision of Noturus an examination was 

 made of most of the recognized species of Ictaluridae, consisting of 

 Pylodictis olivaris (Rafinesque), Satan eurystomus Hubbs and Bailey, 

 Prietella phreatophila Carranza, Trogloglanis patter soni Eigenmann, as 

 weU as over a dozen species of Ictalurus and the members of the genus 

 Noturus described below. Most were represented by ample material, 

 but only three specimens of Satan eurystomus and two of Trogloglanis 

 pattersoni were available, having been described previously by Hubbs 

 and Bailey (1947) and Suttkus (1961). Skeletonized preparations of 

 Pylodictis, Prietella, most species of Noturus, and over half the species 

 of Ictalurus were studied. 



The family comprises three relatively wide-ranging genera, and 

 three genera that are known only from localized underground waters. 

 The genera from underground waters show similarities to one each of 

 the wide ranging genera: Prietella Carranza to Noturus Rafinesque, 

 Satan Hubbs and Bailey to Pylodictis Rafinesque, and Trogloglanis 

 Eigenmann to Ictalurus Rafinesque. The six genera can be arranged 

 conveniently into three major groups, which are here termed the 

 Noturus group, the Pylodictis group, and the Ictalurus group. No 

 taxonomic name is assigned to them, however, because the suggested 

 relationship requires further study. A comparison of the genera and 

 indication of their relationship is presented in table 1. 



Certain characters (not listed in table 1), long used as the bases 

 for genera, appear to have value chiefly in delimitation of species. 

 Of these, the shape of the group of teeth on the premaxillary bone and 

 the shape of the caudal fin have been extensively used. Trogloglanis 

 pattersoni has no teeth on the lower jaw or the premaxilla. The 

 premaxillary teeth in the other genera are arranged in a transverse 



