644 BASHFORD DEAN, 



swarm has been observed to be approximately uniform, the iüdividual 

 diöerences depending rather upon size than upon actual developmental 

 advances; larvae of apparently the same stage of development have 

 varied in length as much as ^Ig inches; in some cases, however, the 

 ränge in development seems, as nearly as could be determined, to 

 have been equivalent to a difference of two or three days. 



Upon the dispersal of the swarm the larvae appear to make 

 their way to the well-weeded shallows of the neighborhood ; here 

 they remain during the first summer, occasionally taken along 

 adjacent shore reaches in the drawing of the minnow nets. Mr. 

 Henry G. Meyer, to whom the writer has hitherto referred for his 

 kindness during collecting trips, has stated that during the first 

 summer many of the fishes will be taken in and near the mouths of 

 the small strearas which feed the lake chain of Pewaukee. It may 

 at all events be surmised that the habits of the late larvae of Ämia 

 do not differ widely from those of the prevailing forms of the local 

 Teleosts. 



II. Description of laryae of Amia, 



The latest embryonic stages of Amia correspond more closely to 

 those of Lepidosteus than of Äcipenser, the embryo's head and trunk 

 lifting themselves sharply above the neighboring parietal zone and yolk. 



Embryo surrounding 200^ of the egg's circumf erence. 



At about two days before hatching (138 hours), PI. 9, Fig. 1, 

 the embryo surrounds about 200 "^ of the egg's circumference. Its 

 trunk, a prominent whitish ridge, is of equal diameter from head to 

 tail ; it is sharply marked ofif from the yolk mass, which at this stage 

 is elongated transversly to the axis of the body. The parietal zone, 

 p.0., is a distinct band, bordering on the one band the line of the 

 primitive Segments and on the other the marginal yolk. The peri- 

 cardial area, p, is now large in size and its distended sides may be seen 

 on either side of the head. The tail is blunt ended, as yet un- 

 separated from the yolk. The head is large; optic lobes are pro- 

 minent, 0. ?., overhanging a broad and deep fourth ventricle ; sucking 

 disc, nasal pits and auditory sacs are already defined; in the eyes 



(females, therefore, as well as males — although uo dissections were 

 made to determine sex) had acquired the characteristic coloration of 

 the male with the prominent orange and black spot on the caudal fin. 



