S. I. Smith — Early Stages of the American Lobster. 367 



below the tip, and the two upon the inner side are still further from 

 the tip than in the second stage. 



The second maxillae have not changed from the last stage, ex- 

 cept in a slight increase in the number of setfe iipon the lobes of the 

 endognathus, and a similar increase in the stout plumose hairs upon 

 the margins of the epignathus, of which the posterior lobe is a little 

 broader than in the second stage. 



In the first maxillipeds (plate XYI, fig. 7, enlarged 40 diameters), 

 the anterior portion of the endognathus is proportionally larger and 

 the spines upon its inner margin are more numerous than in the first 

 and second stages. The mesognathus has the same number of term, 

 inal setaj (fig. 7«, enlarged 100 diameters) as in the earlier stages, but 

 there are several short hairs along the outer margin, and three setse 

 upon the inner side of the distal end of the basal segment. The exo- 

 gnathus has increased considerably in length, and its extremity has 

 begun to show slightly the flagelliform character, although there are 

 as yet no distinct articulations, and only three or four short hairs on 

 the inner margin near the tip. 



In the second maxillipeds, the endognathus has become slightly 

 compressed and the meral segment is longer in proportion, but other- 

 wise is nearly as in the first stage. Tlie exognathus has increased 

 somewhat in length, and the terminal portion shows two or three dis- 

 tinct segments and several quite long plumose and jointed hairs, thus 

 clearly indicating its flagelliform character. The epignathus (plate 

 XVI, fig, 11, enlarged 40 diameters) has increased slightly in size, and 

 the branchial appendage at its base appears as a well defined lobe 

 (fig. ll,c) longer than the breadth of the epignathus itself. 



The external maxillipeds show a slight change toward the adult 

 form. They have not increased in size so rapidly as the legs, and the 

 form and proportions of the segments of the endognathus are quite 

 difierent, the segments being slightly flattened and angulated on the 

 inner margin, the ischial, meral and projDodal segments about equal 

 in length and longer than the others, the articulation between the 

 ischium and merus oblique, and the distal portion carried bent in- 

 ward by a marked geniculation between the merus and carpus and a 

 slight one between the pi'opodus and dactylus. The terminal seg- 

 ment also is longer and more slender than in the earlier stages, and 

 the spines at the tip and on the whole inner margin of the endogna- 

 thus are proportionally smaller, although of about the same number 

 as in the adult. There are no indications of teeth or crenulations 

 upon the inner margin of the ischium. The exognathus is relatively 

 shorter than in the earlier stages, having increased scarcely at all in 



