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



The following measurements of single specimens of the difterent 

 stages of the larv?e, of the earliest stage of the adnlt form, and of two 

 small specimens of diiferent sizes of the adult, illusti-ate better than 

 the descriptions and figures the relative increase in size in the Avhole 

 animal and in some of the parts. The length of the rostrum is taken 

 from the jjosterior margin of the orbit, the lengths of the external 

 maxilliped and the cephalothoracic legs from the base of the epipodus 

 or epignathus to the extremity of the dactylus, and the length of the 

 propodus and dactylus includes in each case the terminal styliform 

 portion. 



First Second Third Earliest Small Small 

 larval larval larval form of adnlt, adult, 

 stage, stage, stage. adult, female, male. 



Length from tip of rostrum to end of telson, 7-9"'"' 10-6'"™ 13-0™" 14-0°"" 80-"™ 132-«"» 



" of carapax to tip of rostrum, 3'6 5*1 6'6 6'8 36'6 GT 



" " rostrum, I'l 2-.') 3-0 2-7 9-5 16-0 



Breadth of carapax, IG 2-2 2-7 2-4 16-4 26-2 



Length of antennula, 1-0 1-2 1-6 29 24/ 38- 



'• inner flagelhim of antennula,. 0-0 -43 -66 1-6 18 28- 



" " outer " " " 00 -62 "88 17 16-5 25- 



" " fiagellum of antenna, -66 1-05 1-80 7-3 76" 120- 



" " antennal scale 1-00 1-25 1-40 1-2 5-0 8 1 



" '• external maxilliped, 27 3-3 3-6 41 23-G 340 



" " first cephalothoracic leg, right, 25 3 3 46 9-0 58- 102- 



" its propodus, -. -8 1-4 20 4-2 33-6 02-4 



" " dactylus, -7 -8 -9 2-0 17-1 34-2 



Breadth of propodus, 4 -5 -7 1-0 13-0 19-4 



Length of first cephalothoracic leg, left,-. 2-5 33 4-6 9-0 60- 99- 



" its propodus, -8 1-4 20 43 350 56 



" " dactylus, "7 -8 -9 2-0 19-2 27-9 



Breadth of propodus, -4 -5 -7 1-0 107 24-8 



Length of second cephalothoracicleg, .- . 25 2-9 3-7 G-2 38- 61- 



» " its merus, "45 -66 1-00 2-1 14-0 21-8 



" " carpus, -25 -36 -45 "8 5-6 9-3 



" "propodus, -70 -86 117 1-8 12-0 185 



" dactylus, -72 "66 -60 -8 4-9 9-0 



" " third cephalothoracic leg, 2-5 2-9 3-6 6-0 37- GO- 



" fourth •' " 2-4 2-8 3-6 6-0 38- Gl- 



'• fifth " " 2-3 2-8 3-7 5-7 35" 55- 



" " its merus, -38 -54 "75 I'G 9-3 14-5 



" carpus, -28 -35 "38 -7 4-2 7-2 



" "propodus, -50 -62 -75 1-6 9-1 14-2 



" " dactylus, -75 -82 -80 -8 4-8 7-1 



" "abdomen, 4-4 5-4 6-4 7-2 44- 70- 



" telson, 1-7 2-0 2-2 2-0 10-3 17-0 



Breadth of telson at base, -6 -9 1-0 1-4 97 162 



" " " across its extremity, .. _ 2-1 2-2 2-2 15 65 11-5 



Length of appendage of third segment, . . 00 -90 1-5 2-2 112 17- 



" " its lamellae, 00 -52 1-0 1-3 6-5 10- 



