10. BETROPDfNA. 171 



Malottus villosus, Cuv. ^ Val. xxi. p. 392, pis. 622 (male) & 623 



(female). 

 ? Osmerus microdon, Cuv. 8f Val. xxi. p. 885, pi. 621 (immature). 

 Salmo (Mallotus) villoaus, Cuv. Regne Anim. ; Richards. Faun. Bor.- 



. Amei: iii. p. 187 ; Gaimard, Voy. en Isl. Poiss. pi. 18. lig. 1. 

 Mallotus arcticus, Kroyer, Danm. Fisk. iii. p. 23. 

 Osmerus arcticus, Nilss. Skand. Faun. Fisk. p. 441. 



B.8-10. D. 13-14. A. 21-23. P. 18-20. V. 8. Csec. pyl. 6. 



Vert. 68. 



The height of the body is much less than the length of. the head, 

 which is contained four times and one-third in the total (withoiit 

 caudal). Snout longer than the diameter of the eye, which is two- 

 ninths of the length of the head. Brownish on the back, silvery 

 on the sides ; opercles silvery, with minute' brown dots. 



Mature males have a band of elongate scales along the lateral line 

 and along each side of the belly ; the base and the margin of the 

 anal fin form a convex curve, and its anterior rays are simple and 

 rather stiff. In very old examples also the scales .on the back and in 

 the middle of the belly project beyond the skin, and the head and 

 the rays of the paired fins are finely granulated. 



Shores of Arctic North America and of Kamtschatka. 



o, 6, c-d, e-f, g-i. Adult males and females. Greenland. 



Ic-l. Adult male and female. Hudson's Bay. From the Hashr 



Collection. 

 m. Adult male. Presented by the Smithsonian Institution. 



10. RETROPINNA. 



Retropuma, Gill, Pt'oc. Acad. Nat. Sc. Philad. 1862, p. 14. 

 Richardsonia, Sleindachner, Sitzgsher. Akad. Wiss. Wien, 1866, p. 53. 



Body covered with scales of moderate size. Cleft of the mouth of 

 moderate width. Small teeth, subequal in size, in single series on 

 the jaw-bones, vomer, palatines, and pterygoids ; tongue with a double 

 series of small hooked teeth. Dorsal fin situated far backwards, 

 behind the ventrals, above the vent ; anal rather long ; caudal forked ; 

 ventral six-rayed. Pseudobranchias present. Stomach horseshoe- 

 shaped, without prolonged blind sac ; pyloric appendages and air- 

 bladder absent. 



Fresh waters of New Zealand. 



1. Retropinna richardsonii. 



New Zealand Smelt. 



Argentina retropinna, Richards. Voy. Ereb. Sf Terr. Ichthyol. p. 121, 



pi. 52. figs. 1-3 (pectoral too long). 

 Retropinna richardsonii, Gill, I. c. 



R. 6. D. 11-12. A. 17-20. P. 11. Y. 6. L. lat. 61. 

 The height of the body is less than the length of the head, which 

 is contained four times and two-thirds in the total (without caudal). 

 Snout shorter than the eye, the diameter of which is two-sevenths of 



