CATFISH GENUS NOTURUS RAFINESQUE 31 



structures. They range from 9.5 to 11.0 mm. (mean 10.3 mm.) in 

 total length or 8.0 to 9.5 mm. (mean 8.8 mm.) in standard length. 

 At this stage, there are no pigment cells, the yolk sac is large, and 

 considerable ossification has taken place. The top of the skull is 

 unossified but the opercle and the jaws are well ossified. The rod-like 

 basioccipital is prominent; back of it, the vertebral column is well 

 developed. Pectoral and pelvic fins are present, with distinct fin rays; 

 however, the number of rays was not determined because of their 

 mangled condition. The pectoral fin has a poorly ossified spine that 

 has no serrae; the dorsal fin has six soft dorsal rays (at least in tliree 

 specimens), a well-developed but rather poorly ossified spine, and a 

 short plate-like spine in front. No pectoral radials are visible. 



The caudal fin at this stage has only 29, 29, and 30 rays, approxi- 

 mately one-half the adult complement; there are no branched rays. 

 There are 14 or 15 (mean 14.8 in 4) anal rays, approximating the 

 number (mean 15.2, see p. 198) in the adults at this locality. The 

 branchiostegal ray complement does not seem to have been attained; 

 there are six to eight rays present. 



In the vertebral column, it can be seen that five vertebrae make 

 up the anterior vertebral complex (Regan, 1911, pp. 553-554), which 

 also were observed in tiny Noturus gyrinus. The most anterior centrum 

 is longitudinally constricted and becomes a relatively free, flat disk; 

 the next two are somewhat restricted in length; the fourth bears a 

 parapophysis (or transverse process), one arm of which is directed 

 forward at about a 45° angle. Its end turns slightly downward and is 

 attached to the cleithrum. The fifth and successive vertebrae have 

 transverse processes that are directed outward at an angle of about 90° 

 to the vertebral axis. In the next larger size examined (see below), it 

 can be seen that the sixth vertebra is the first that bears ribs. It is 

 also the first free vertebra, as the centra of vertebrae 2-5 are nearly 

 fused. This confirms R. R. Wright's (1884a, p. 249 and 1884c, p. 376) 

 and McMurrich's (1884, pp. 294-295) observations. The dorsal spine 

 is supported by a heavy strut extending diagonally backward from 

 the fifth vertebra; the plate-like spine in front connects through a 

 large strut to the fourth vertebra and its transverse process. Poster- 

 iorly, two small centra are present in the upturned caudal lobe; 

 however, whether two, or three, or more are fused into the urostyle 

 could not be determined. 



Two other lots of 10 and 11 specimens of Noturus miurus were 

 stamed. The first is a brood at least 12 days old, ^vith a range of 

 from 14.7 to 16.0 mm. in total length and from 12.0 to 12.8 mm. 

 (mean 12.5 mm.) in standard length. The 11 fish in the second brood 

 died at various times, from three to five weeks after collection. They 

 range from 14 to 17 mm. in total length and from 11.5 to 13.4 mm. 



