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



The ocular peduncles are very short and thick, directed straight 

 outward, and apparently admit of only a small amount of motion. 

 The cornea projects very slightly beyond the margin of the carapax 

 and is very large, its diameter being about a third as great as the 

 breadth of the carapax. 



The antennulre (plate XV, fig. 6, enlarged 30 diameters) are short, 

 simple, sack-like appendages, about half as long as the rostrum, 

 slightly contracted proximally, and entirely without division into seg- 

 ments. At tip they are each furnished with three simple sette, one 

 stout and about half as long as the antennula itself, the others very 

 small and placed at the base of the larger. No sign of auditory ap. 

 paratus could be discovered. In one specimen, which Avas approach- 

 ing the time of molting, the antennula^ of ohe next stage was plainly 

 visible through the integument (plate XV, fig. 7, enlarged 30 diame- 

 ters), and show distinctly two separated segments representing the 

 peduncle, the partial separation of the secondary, or inner, flagellum, 

 and the hairs toward the tip of the outer flagellum. 



The antennae (plate XV, fig. 11, enlarged 30 diameters) are slightly 

 longer than the antennulae and much further developed. There is a 

 sharp tooth at the base of the scale. The scale itself is highly de- 

 A'eloped and resembles considerably that of many of the Mysidea. It 

 is broad, considerably longer than the flagellum, armed with a sharp 

 tooth at the extremity of the outer margin, and the inner edge is 

 furnished with very long plumose hairs, which are jointed throxigh 

 most of their length, and taper to very slender tips. The flagellum is 

 shorter than the scale, separated from its peduncle by an articulation, 

 but is itself not divided into segments, and is naked except at the 

 tip, which is furnished with three equal, slender, plumose hairs like 

 those upon the scale, only somewhat shorter. 



The mandibles (plate XV, fig. 13, enlarged 25, and fig. 14, enlarged 

 40 diameters) are delicate and the crowns alone indurated. The palpi 

 are very small, short and cylindrical, the three subequal segments 

 faintly indicated, and the tip of each furnished with two short hairs. 

 They are directed straight forward and apparently have no power of 

 acting wnthin the edges of the mandibles as in the adult. The coi'onal 

 edges of the mandibles are asymmetrical. In both there is a very small 

 molar-like area (fig. 14, h) at the posterior angle covered with fine 

 teeth or bristles, and, in front of this, the margin, nearly to the anterior 

 angle, is armed with acute spiriform teeth which are hooked slightly 

 backward. At the anterior angle this margin is turned abruptly 

 backward for a short distance below (in the natural position of the 



