56 U.S. NATIONAL MUSEUM BULLETIN 2 82 



the lower caudal lobe) are fused, and hypurals 4-5 (in upper caudal 

 lobe) are fused. The pectoral radials are fused on both sides. 



The color in life of the holotype was reported to be dark brown; 

 when in the water it resembled a darkly colored young bullhead. 

 No bright colors were present. 



The Tulane specimens are nearly transparent — evidently because 

 of faulty preservation — and have virtually no pigment. The holotype, 

 in preservation, is dark grayish brown above, grading to slightly 

 lighter on lower side, and pale whitish below. Widely scattered 

 chromatophores cover the entire lower surface of the head, an area 

 about the base of the pelvic fins, and the side of the abdomen; the 

 middle of the abdomen is immaculate. Heavy dark pigment is on the 

 chin in front of the mental barbels; a small unpigmented area sur- 

 rounds the vent. The vertical fins are similar in color to the upper 

 body surface; the paired fins and barbels are similarly pigmented but 

 lighter. The remaining paratypes are yellowish brown, and presum- 

 ably extensively faded as the upper chromatophores are not prominent 

 and the abdomen and lower surface of the head are devoid of distinct 

 pigment cells. 



Type. — The holotype of Noturus lachneri is an immature female, 

 40.0 mm. in standard length. It has 17 anal rays, 6 soft dorsal rays, 

 37 vertebrae (of which, judged from a radiograph, 8 are precaudal, 

 29 are caudal, and 12 are anterior to the anal fin origin), and 25+8 + 

 13 + 14=60 caudal rays. On each side there are 8 pelvic rays, 8 soft 

 pectoral rays, 10 preoperculomandibular pores, and a single internasal 

 pore. There also appear to be six hypurals, of which the lower three 

 (1-3) are fused, and one epural. The head length is stepped 3.9 times 

 in the standard length and the distance from the rear end of the 

 adipose fin to the tip of the caudal fin is stepped 1.35 times in the 

 distance from the dorsal origin to the posterior end of the adipose 

 fin. There appear to be eleven branchiostegal rays on the right side, 

 in agreement with counts obtained from a cleared and stained para- 

 type. Measurements are given in table 27. 



Distribution. — Noturus lachneri is known only from three localities 

 in the Saline River system, Arkansas, a tributary to the Ouachita 

 River. 



Relationship. — The ten preoperculomandibular pores and terminal 

 mouth suggest a relationship closest to Noturus exilis and Noturus 

 gyrinus. In several characters including number of vertebrae, anal 

 rays, and pectoral rays it is intermediate between the two species. 

 The dark, nearly uniform color, lack of pectoral spine serrae, modal 

 number of eight pelvic rays, and large number of caudal rays are 

 characters similar to those of N. gyrinus, but the fusion of the anterior 

 ends of the infraorbital and supraorbital canals, the short flattened 



