820 S. I. Smith — Early Stages of Hippa talpoida. 



curled up closely beneath the sternum, and, in all the specimens 

 examined, show the segments of the succeeding stage faintly indi- 

 cated within. The posterior thoracic legs appear to be represented 

 by a small process each side, just back of, and nearly hidden by, the 

 rudimentary fourth pair. Four pairs of gills on each side are repre- 

 sented by two slender processes, one above the other, at the bases of 

 each of the four anterior pairs of legs 



The proximal segments of the abdomen are almost exactly as in 

 the previous stage, except there are very slight elevations beneath 

 the second, third, fourth, and fifth segments, where the rudimentary 

 legs are to appear in the succeeding stage. The sixth segment is 

 still consolidated Avith the telson. Its appendages (Plate XLVIII, 

 fig. 11) have increased much in size and the inner lamella (c, fig. 11) 

 has appeared as a small, sack-like appendage at the base of the outer 

 lamella {b, fig. 11), which is twice as long as in the previous stage, 

 very narrow, only slightly expanded in the middle, and sub-truncate 

 at the extremity, where it is furnished with four slender and curved 

 setoe, of which the median ones are longer than the lamella itself, 

 while the outer are little moj-e than half as long. The telson is of 

 the same form as in the previous stage and has the same number of 

 ciliated spines in the armament of the posterior border, while the 

 number of denticles in the interspaces has considerably increased, 

 though they are not as numerous as in the succeeding stage. In one 

 specimen there is the same abnoi-mal arrangement of the spines 

 described under the second stage, that is, there are only twenty-five 

 spines in all, one median spine taking the place of the two sub-median 

 spines and the denticles separating them. 



The young in this stage were taken on several occasions, both in 

 the day-time and evening, from August 28 to September 8. Their 

 habits and coloration in life were the same as in the last zoea-stage. 



Last zoea-stage. 



The length from the tip of the rostrum to the posterior margin of 

 the carapax and the breadth between the tips of the lateral spines 

 are nearly twice as great as in the second stage, while the rostrum is 

 relatively considerably longer than in either the second or the third 

 stage, its entire length being nearly twice that of the carapax proper. 

 The general form and appearance of the young in this stage are 

 shown upon Plate XLV, figs. 2, 3, 4. 



The eyes and ocular pediincles are very little larger absolutely 

 than in the last stage. The diameter of the cornea is scarcely a 



