476 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



PLATE YTT. 



FIG. 10. Left second maxilla, of larva at the point of hatching, before the first molt, x 276. Coin- 

 pare with Figs. 25 anil 21. 



FIG. 11. First swimming larva, after the first molt, seen from below. Pigment cells, brown. 

 L= jJjft, in.- (measured from tip of rostrum to median notch of telson). Length of 

 rostrum = T $ in. x 70. 



FIG. 12. Right first maxilla of first larva, seen from the outer side. Setae rudimentary. Compare 

 Figs, lit, 25. x276. 



FIG. 13. Telson of larva before first molt, seen from below. Compare Fig. 11. The set* are 

 invaginated and covered with a loose cuticle. x276. 



FIG. 14. Right first maxilliped of larva on the point of hatching, seen from the outer side. Setre- 

 tnvaginatod. Compare Figs. 22, 25. x276. 



FIG. 15. Labrum and right mandible of larva, seen from above. x276. 



FIG. 16. Right third maxilliped of larva on the point of hatching, seen from the outer side. Com- 

 pare Fig. 25. x 276. 



REFERENCE LETTERS. 



a, outermost spine in telson of larva at the point of hatching. 

 d, equivalent of a in first locomotory larva. 

 Lb, labrum. 



