1894. 



PROCEEDINGS OF TEE NATIONAL MUSEUM. 



547 



ill alcohol and is represented in fig-. 27. The other was left in the 

 aqnariiim, and on July 9 it molted in the form seen in fig. 28. rnfor- 



tnnately the two larva? 

 were not compared care- 

 fully before the molt, but 

 I have no doubt that they 

 were identical inform, for 

 there was no difference in 

 general appearance, and 

 a careful comparison of 

 the specimen represented 

 in fig. 27 with the older 

 one in fig. 28 shows so 

 many features in common 

 that one can hardly doubt that the one form is 

 derived from the other, and this opinion is con- 

 firmed by the entire absence of any characters 

 inconsistent with such a view. Of course, these 

 two forms are separated by the critical change 

 from the larval to the adult form, and there is 

 more difference between them than between any 

 other two stages. 



The adult form (fig. 28) appears to be iden- 

 tical with Sijuilla quadridenSy Bigelow, the type 

 s])ecinien of which was found on the Florida 

 coast not far from where these larvre were cap- 

 tured. A comparison of the figure with the de- 

 scription of the species (p. 511) will show that 

 it corresponds in all the chief characters, al- 

 though it probably would not assume its fully 

 matured form and detail of structure until after 

 several more molts. In the passage from the 

 larval to the adult form the body becomes 

 broader and more compact at the expense of its 

 length, so that shortly after the molt it is but 

 1.1 cm. in length, while before it was 0.5 cm. 

 longer. Another specimen which may have 

 undergone another molt since assuming the 

 adult form was captured by. the towing net 

 four days later. 



The dactylus of the raptorial limb in the larva 

 (fig. 27) is unarmed, but one can see three 

 lateral teeth in addition to the terminal one 

 lying beneath the larval skin. In this way it 

 corresponds to the adult form, and at the 

 same time recalls Brooks's description (188G, pp. 90-93), of Squilhi 

 (Alima) bidens, Glaus, but a comparison of this description and the 



Fig. 27. 



LAST ALIMA STAGE OF SQUILLA 

 QUADRIDENS. 



