504 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



PLATE XXI. 



Fit',. 1. First larva of Al/tlti-nn xmtlri/i, var. hrcriatrjms, from "loggerhead" spouge. Hatched at 



4 p. in., June. 10, 1887. A small amount of uuubsorbed food yolk remains in the 



stomach. x2(J. 



FIG. Itf. Liue to indicate length of larva. L.=.'!.5""". 

 FIG. 2. Second larva of .same, from brood hatched on evening of June 8. Food yolk nearly 



absorbed. About twenty-four hours old. xli<>. 

 Km. ~a. Line to .show length of larva. L.=4""". 

 FIG. 3. Head of young from same brood. Four days old. X' r >2. 

 FIG. 4. Right tirst pereiopod of larva of A. xitnlcyi, var. brevicarpus, before the molt preparatory 



to stage shown in Fig. 1. Seen from inner side. x52. Swimming hairs of exopodites 



rudimentary. 

 FIG. 5. Egg embryo of .4. suiilcyi, var. lonyicarpus, nearly ready to hatch. The large chela of the 



left first pereiopod is conspicuous below the, antennae. x46. 



FIG. 5. To show natural si/.e of the same. Slightly too large. Dimensions: riro x Tcb inch. 

 FIG. <>. First and second maxilla of first larva (Kig. 1) before preparatory molt. The parts are 



gloved with the embryonic skin, which is usually cast off at the time of hatching. 



X227. 



FIG. 7. Left first pereiopod of same, seen from inner side. x52. 

 FIG. 8. Third larva of Aljihrux xuulcyi, var. lin-ricar/Hix. From same brood as second larva, Fig. 



U. Not over twenty-eight hours old. Food yolk not wholly absorbed. x2G. 

 FIG. !l. Telson and rudimentary uropods, seen from below. x32. 



