CATFISH GENUS NOTURUS RAFENESQUE 183 



blotch is submarginal, rather than extending to the extreme margin. 

 Otherwise the color patterns in each river system are very similar. 



The following summaries of the data include the number of counts, 

 range (in parentheses), and means for (a) Pearl River system, (b) 

 Tombigbee River, and (c) Cahaba River. 



Vertebrae: (a) 65 (30-33) 31.20; (b) 60 (30-33) 31.72; (c) 13 (30-32) 

 30.92. 



Anal rays: (a) 74 (12-14) 12.88; (b) 60 (12-15) 13.47; (c) 13 (12-14) 

 13.23. 



Upper-half caudal rays: (a) 74 (23-26) 24.34; (b) 60 (23-27) 24.85; 

 (c) 13 (23-27) 24.69. 



Lower-half caudal rays: (a) 74 (21-26) 22.95; (b) 60 (22-24) 23.07; 

 (c) 13 (22-25) 23.54. 



Total caudal rays: (a) 74 (45-52) 47.28; (b) 60 (45-51) 47.92; (c) 13 

 (46-52) 48.23. 



Soft pectoral rays: (a) 148 (7-9) 7.93; (b) 120 (7-8) 7.93; (c) 26 

 (7-8) 7.81. 



Preopercul&mandibular pores: (a) 142 (9-12) 10.95; (b) 120 (9-12) 

 10.89; (c) 26 (10-12) 10.77. 



Although the Pearl River specimens generally have lower mean 

 numbers of anal and caudal rays than do the populations in the 

 Tombigbee and Alabama River systems, the differences do not seem 

 to indicate a significant divergence in any of the river systems. 



Distribution (map 13). — Noturus munitus ranges from the Pearl 

 River in Louisiana and Mississippi eastward to the Cahaba River, 

 a tributary to the Alabama River, Alabama. It seems to be confined 

 to the lower portion of the Pearl River and its larger tributaries. In 

 the MobUe Bay drainage munitus is probably found throughout most 

 of the Tombigbee River and likely wUl be found to have a more ex- 

 tensive range in the Alabama River system. 



Etymology. — The name munitus (Latin), means armed or pro- 

 tected, and is used in allusion to the excessively large spines and serrae. 



Relationships. — Features of pigmentation, expecially the dark 

 adipose blotch and the two crescentic caudal bars, in addition to the 

 body shape, the long posterior process of the cleithrum, and the 

 relatively free posterior edge of the adipose fin indicate a relationship 

 with the other species of thefuriosus group. 



Ecology. — Noturus munitus is found chiefly on riffles and in rapids 

 of rivers and their larger tributaries. It apparently avoids small streams 

 and still-water habitats. Species that have been collected with it are 

 Noturus miurus, Noturus leptacanthus, Noturus nocturnus, and Noturus 

 funebris. 



