328 jS. I. iSmUh — Early Stages of Hippa talpoida. 



Tlie distal extremity of the palpus is foliaceous, the margins obtusely 

 rounded and armed with long, plumose setae, which extend over the 

 oral edge of the labrum and the anterior edge of the mouth itself. 

 The outer margin (c), which is thickly spinous in the adult, projects 

 considerably laterally, but is, as yet, armed with only three or four 

 spines. 



The first pair of maxilla? (Plate XL VI, fig. 13) have assumed the 

 general form and arrangement of parts which they present in the adult. 

 The inner lobe («, fig. 13) is relatively larger than in the zoea-stages, 

 being considerably broader than the outer lobe ; and is armed at the 

 tip, and a little way down the inner margin, with long and stout 

 seta3, most of which are slightly spinulose or plumose distally. The 

 outer lobe (i) is long, rather narrow, and the terminal margin is 

 obtusely rounded and armed with setiform spines, which are short 

 and stout toward the inner margin but increase in length outward, 

 and, at the outer margin, grade suddenly into very long and slender, 

 plumose setae, of which the outermost one is nearly three times as 

 long as the width of the lobe itself. On the inner, lateral margin 

 there are several plumose hairs and on the outer margin, a single 

 sliort spinule. The palpus (c) projects laterally from near the base 

 of the outer lobe as an irregular, sack-like appendage. The articula- 

 tion at the base of the inner lobe is much less distinct than in the 

 adult, although the articulation at the base of the outer lobe is 

 conspicuous. 



The peculiar structure of the mandibles and maxillne of the adult 

 are more fully discussed in a special note at the end of this article. 



The second pair of maxillae (Plate XLVII, fig. 3) have assumed 

 nearly the adult form. The lobes of the protognath («, i, fig. 3) are 

 deeply separated, and a small, supplementary, papiliform lobe («'), 

 tipped with a long, plumose seta, has appeared between the inner and 

 outer lobe, arising near the base of the inner. The terminal margin 

 of the inner lobe is armed with plumose setae, arranged in three 

 series of varying lengths, the longest, situated upon the very edge, 

 being nearly as long as the lobe itself The outer lobe is similarly 

 armed, but the setie are all much shorter and less plumose, and some 

 of them are stout and serrate. Between the outer lobe and the 

 anterior projection of the scaphognath, there is a small, triangular 

 lobe {d) apparently representing the endognath. The characteristic 

 fringing of plumose hairs has extended round upon the inner margin 

 of the broad, posterior portion of the scaphognath (e), which has 

 changed comparatively little since the last zoea-stage, ))ut still is of 



