Occasional Papers of the Musciini of Zoology 5 



of eye diameter. Hind preopercle edge evenly convex, free. 

 Opercle width i 1/5 its depth. 



Gill-opening extends forward opposite front pupil edge. 

 Rakers 6 -j- 13, lanceolate, 3 in eye. Filaments i 3/5 in eye. 

 Pseudobranchise about a third of eye. Isthmus narrowly con- 

 stricted. Branchiostegals 10 -{- 10, upper little larger. 



Scales rather small, disposed in even longitudinal series par- 

 allel with lateral line, mostly of about uniform size, cycloid and 

 each scale well exposed. Preventral and front predorsal re- 

 gions finely scaled though breast anteriorly naked. Ventral 

 with scaly axillary flap. L. 1. complete, about midway along 

 side and each scale with a simple tube extending about first 

 half over each exposure. 



Dorsal origin about first third in space between snout tip 

 and caudal base, graduated up to first branched or longest ray, 

 other branched rays but slightly shorter. Adipose fin origin 

 about midway between depressed dorsal tip and caudal base, 

 fin 4 to caudal base. Caudal forked, lobes pointed, about equal. 

 Anal origin a little nearer last branched dorsal ray than caudal 

 base, first branched ray longest and falling a little short of last 

 when depressed, fin i 2/3 to caudal base. Upper pectoral rays 

 longest, fin about half way to ventral. Latter inserted about 

 opposite middle of dorsal base, fin half way to anal origin. 

 Vent? 



Color in alcohol faded, largely dull or pale brownish, sil- 

 vered or whitish below. Fins all pale brownish and all median- 

 ly and terminally with' somewhat dusky shades. Iris brownish. 



Length about 1 79 mm. ? 



No. 7,796, A. N. S. P., type of Thyniallits tricolor Cope. 

 Au Sable River, Michigan. E. D. Cope. This example in very 

 poor preservation several years ago, when the above descrip- 

 tion was made. 



