298 PROCEEDINGS OP THE AMERICAN ACADEMY 



In the next stage figured the young Osmerus is considerably older, 

 measuring already 22°^°^ in length ; the caudal is completely separated 

 from the dorsal and anal, in both of which the permanent fin rays 

 already exist ; there are rudimentary ventrals present in this stage. 

 The general coloring of the body is a light dirty yellow, with patches 

 of more brilliant yellow along the lateral line and base of the head. 

 There is one line of greyish pigment spots along the dorsal side of the 

 notochord, a very prominent line of large pigment cells running some- 

 what below the notochord, extending from the base of the pectorals 

 to the vent, with four or five large pigment cells along the base of the 

 anal and the ventral line towards the base of the caudal. Small pig- 

 ment spots extend along the base of the caudal fin rays, with three or 

 four larger spots at the base of the caudal fin. The oldest stage I 

 have found (Plate XII. fig. 5) was not larger than Plate XII. fig. 4, 

 but the caudal, anal, and dorsal were in a more advanced condition, the 

 permanent fin rays better marked, the head less elongate, the body 

 behind the ventrals comparatively broader. The great resemblance 

 of this stage of Osmerus to Scomberesox and Belone in the general 

 arrangement of the median fins and the great elongation of the body 

 is striking. Mr. H. J. Eice has, in the Report of the Commissioner 

 of Fisheries of Maryland for 1877 (Plates III. V.), given excel- 

 lent figures of several young stages of the Smelt. The figures here 

 given complement the stages already known, and with those of Mr. 

 Rice give a fair sketch of the principal changes of the Smelt due to 

 growth. The resemblance of the development of Osmerus to that of 

 the Herring as given by Sundevall is very striking. Sundevall figures 

 young fishes, which he calls embryo Herring, from 8 to 3S^^ in 

 length, but he does not state whether they were actually raised from 

 eggs of known origin. Before the publication of Mr. Rice's paper I 

 had already supposed the young fishes figured on Plate XII. to be the 

 young of some Clupeoid, but the figures given by him seem to leave 

 no doubt that the young I figure on Plate XII. belong to the Smelt. 



