MEMOIRS OP THE NATIONAL ACADEMY OP S0IBNOB8. 345 



Figs. 14 and 10, which represent the first and third inaxilliped.s of the right side, as seen from 

 below. The eudopodites of the second and third pairs possess four joints, of which the terminal 

 one carries seta^. There is one jiair of thoracic limbs consisting of a stont locomotive exopodite, 

 similar to that of the second and third maxillipeds just desciribed, and of a very short, indistinctly 

 segmented endopodite. The latter is armed with two terminal and three lateral plumose hairs on 

 tbe inner side. 



H. First zoe'a or second larva (length, a=~)"""). — Five or six hours after hatching the pro- 

 tozoea moults into a form which superficially resembles the inacrouran larval type. (PI. Vlll, 

 Fig. 17.) The carapace of this larva has grown down so as to cover the basal Joints of all tbe 

 appendages, and it also extends behind them. The rostrum is reduced to from one-half to two- 

 tbirds its former size, and does not surpass tbe autenual hairs. 



There is still pat one thoracic segment with its appendages. All tbe abdominal segments are 

 formed, but none show any traces of limbs. The lateral spines of the first and second somites are 

 missing, but the median unpaired spine of tbe latter is greatly developed, and extends to nearly 

 tbe end of the third somite. The sixth somite, which carries the zotial tolson, is equal in length to 

 the third, fourth, and filth combined. The fjinsbaped telson, viewed from below, is represented 

 in Fig. :iO. Comparing this with Fig. 11, we observe that it is no longer conspicuously forked. 

 The median notch has a short unpaired spine. There are six pairs of feathered hairs, the outer- 

 ones still being rudiments exactly as in tbe first larva, aud a uon-plumose spine which ends the 

 series; the three rudimentary spurs seen in Fig. 11 being wanting. The eyes, which have acquired 

 short stalks, protrude slightly. 



The autenujB are shorter and are now no longer so important as organs of locomotion. The 

 terminal joint of the inner antenna is rediured, but otherwise this appendage is but little changed. 

 The outer antenna ends in a stout hook, whi(!h is succeeded, on the indented margin of the inner 

 side, by a series of eight feathered hairs. The second joint of this appendage also bears a serrated 

 hooked spine at its outer extremity. The mandible is without a i)alp. It has a serrated edge, 

 and a prominent, inferior, compound tooth (Fig. 18). 



The inner branch (coxopodite) of the first maxilliB (Fig. 19) carries three simple and three com- 

 pound s])ines, while the outer division consists of three segments with stout, plumose hairs, as shown 

 in the figure. The second maxilla^ (Fig. 21) are considerably altered from the form shown in Fig. 10. 

 There is an outer lobe (scapliognathite), bearing one large hair directed backwards aud at least 

 four others which jjoint in the <)|>posite direction. The inner i)ortion is lobulated into six or more 

 parts, all of which are well [jrovided with stifl' hairs.* 



Tbe first maxillijjed is shown greatly enlarged in Fig. 22. Examining this in connection with 

 Fig. 14, we find that tlie exopodite consists of one segment aud bears a limited number of hairs 

 (here twoj at its a])ex. The eiulopodifc^ is segmented and carries numerous hairs, which are 

 continued in small tufts along the inner margin to tbe base of the limb. The (rhief swimming 

 organs are the first and second maxillii)eds and the first pair of thoracic legs. The inner branch 

 of the latter is considerably developed, and nearly equals the exjtodite in length. 



There is a large irregular spot of red jiigment on each side of the anterior half of the body 

 just above the base of the third maxilliped. The lobes of the liver (L) begin now to show dis- 

 tinctly through the carapace. The food yolk, which is present in small quantities in the stomach 

 of the protozoca (Fig. 2'>), is finally absorbed. It was probably owing to this and to the fact that 

 I gave the larVa' no food that suited their taste that they never reached the second moult, although 

 they i)assed a number of days in this condition. In course of several trials the animals at this 

 stage always became greatly crii)pled by i)articles of organi(! matter adhering to theii' body and 

 invariably starved. For later stages, therefore, connecting this zoi'-a with tbe adult, we have to 

 rely ujwn larvte collected at the surface of the ocean. 



<!. Ml/sis or Scliiznpotl stage. — It is evident that the zoea of the stage B pass(>s into a mysis- 

 like form through the intervention of one or more moults, and we have two larvae already noticed 

 belonging to the close of this jjcriod. They were collected by at Beaufort, N. C, July 14 and 15, 



* Tbe ditital or termiuul lobe represents tbe endopodite ; tbe lobes next tbis stand for tbe basipodite, while tbe 

 second (f) proximal division at tbe base of tbe appendage correspond to the coxopodite. 



