Jordan and Evermayin. — Fishes of North America. 20G1 



species ; 3 in front of spinoiis dorsal, 11 (or 12) along base of spinous dorsal, 

 2 (or 1) between dorsals, 6 at base of soft dorsal, 14 (or 13) unpaired 

 plates on back of caudal peduncle. The unpaired plates with the spine 

 notched at tip; all the plates marked with strong radiating ridges aTid 

 the surface of the spines minutely roughen ed. Color, light gray above, 

 white below; top and sides of head with black dots and dashes; back 

 crossed by six narrow black bars. Distinguished from all other species 

 of the genus by the great development of the lateral ridge and spines ou 

 head. This gives the head and especially the snout a much broader outline, 

 approaching in this respect Agonus cataphractus. The species is repre- 

 sented by several young specimens in rather poor condition, the type 

 being 53 mm. long. The outline and armature of the head are not, how- 

 ever, essentially difterent in young and adults of such species as are 

 known to us from specimens of different sizes. Off Shana Hay, Iturup 

 Island, Kuril Group. (This species is named in honor of Prof. D'Arcy 

 Wentworth Thompson, of the University at Dundee, the commissioner of 

 Great Britain in the fur seal investigations in Bering Sea in 1896 and 

 1897.) 



Fodothecus tkompsoni, Jord.\n & Gilbert, Kept. Fur Seal Invest. 1896, 1897 MS., off 

 Shana Bay, Iturup Island, at Albatross Station 3653, in 18 fathoms. (Tyi)e, No. 

 5667, L. S. Jr. Univ. Mus. Coll. Albatross.) 



2413. PODOTHECUS ACIPENSERIXUS * (Tileaiua). 



(Common Alligator Fish.) 



B. 6; ID. 8 to 10; 2D. 7 or 8; A. 7 or 8; P. 17 or 18; V. 3 (I, 2) ; C. 1-12-1; 

 vertebne 12 -f- 29 = 41. Pyloric ca^ca 7 (2 individuals). Total length 

 reaches 10 inches. Body as deep as wide, ridges of dorso- and ventro- 

 lateral series strong, while those of the rest are but little developed, thus 

 giving body a sharply quadrangular form in front; dorsal and ventral 

 faces flat between ridges, the lateral convex. Behind middle of first dor- 

 sal the lateral ridges become more prominent and body more regularly 

 8-hedral ; tail 6-hedral, strongly depressed. The strong, curved, minutely 

 serrated spines of the dorsolateral series grow smaller from occiput back- 

 ward and disappear at beginning of second dorsal; superior lateral series 

 spinous from middle of first dorsal to middle of peduncle; inferior lateral 

 series spinous for a short distance from a little in front of to a little behind 

 anal; ventrolateral series keeled, not s])inous. Two pairs of plates 

 between last ray of second dorsal and first median plate, and 2 to 4 pairs 

 between last anal ray and first median plate. About 20 well-developed 



* Diagnosis: Body tapering uniformly from bead to caudal, as high as wide anteriorly, 

 width at base of pcctnrnls 7 in Icnuth -."tail from front of second dorsal to caudal much 

 depressed; head 4: iiliitcs lu cldisal series 87 to 88; between occiput and first dorsal 4 

 pairs; between (l<)r.-i:ils 'J or :; iioin vcntrals to anal 10 to 11 j)airs. Gill memlirancs joined 

 to isthmu.s witlioiii told: noTi.ili on vomer or palatines. A pair of complex groups of 

 liaili'ls on under side of tip of snout, auotluT gr(iu|i at angle of mouth, and a pair of 

 doiihli liMi ImIs :it sides of lower .jaw. Snout with J luiiis of spines, 1 pair directed hori- 

 zoiiiiilly forward, tlie other curving baekwaicl and oiiiward. One pair supraocular and 

 1 pair 01 ii]iital spiues. Color grayish brown, yellowish below ; sides with narrow undu- 

 lating vertical blackish streaks. 



