Family Osmeridae 



HENRY B. BIGELOW 



Museum of Comparative Zoology 

 Harvard University 



and 

 WILLIAM C. SCHROEDER 



Woods Hole Oceanographic Institution^ 



Characters. Essentially as in the Salmonidae (p. 457), but with: sides lacking the 

 Fleshy appendages above bases of pelvics that characterize Salmonidae; last few 

 Vertebrae definitely not upturned; neither an Orbitosphenoid bone separating the 

 orbital depressions of the skull nor a Postotic in the auditory region;- the Bony plate 

 on dorsal side of skull above vomer divided longitudinally by a median suture in some 

 {Osmerus, Allosmerus, Thaleichthys, and Spirinchus) but not in others {Mallotus),^ nor 

 among the Salmonidae;* only a few Pyloric caeca or none (not more than 7 in any 

 western North Atlantic species). 



Remarks. In their general appearance the smelt and capelin closely resemble 

 trout and young salmon, but there is no danger of mistaking the one for the other, 

 for the members of the smelt tribe are slimmer-bodied than the salmons, have more 

 deeply forked tails, and their pelvic fins stand farther forward relative to their dorsal 

 fin (see Key, p. 554); they differ further from the salmons in lacking the fleshy append- 

 ages above the pelvic bases. 



Genera. Six genera seem to deserve recognition within the Osmeridae as defined 

 above, only two of which occur in the western North Atlantic, the others being con- 

 fined to the northern Pacific. Perhaps we should remark in passing that the "smelt" 

 of New Zealand and of New South Wales, Australia, is not a true smelt, but belongs 

 to the related family Retropinnidae, the dorsal fin of which is far posterior to the pelvics. 



1. Contribution No. 1149 from the Woods Hole Oceanographic Institution. 



2. For additional details as to skull characters, see Berg (6: 240, 428). 



3. For proethmoid bones, see Chapman {11: 280-291, figs. 3, 4) and Starks [106: 151, fig. 3, 335). 



4. For dorsal view of the skull of the salmons, see especially Parker (74 : 144, pi. 7, fig. i) and Gregor\' {32 : 154, fig. 48 A, 

 dermethmoid bone). 



5SZ 



