248 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



Plate 43. 



Fig. 166. Bud of right fourth pereiopod iu process of regeneration from young lobster probably in 

 fourth stage. August 3, 1893. 47 times natural size. 



Fig. 167. Part of transverse section of oviduct of lobster, with ovary nearly ripe. July 25, 1893. 270 

 times natural size. 



Fig. 168. Part of transverse section of oviduct of lobster, with external eggs in early yolk segmentation. 

 For a drawing of this ovary see fig. 119, plate, 36. August 3, 1894. 270 times natural size. 



Fig. 169. Longitudinal section of first, second, and third segments of right first pereiopod of young 

 lobster in sixth stage. Plane of section shown in cut 15. Length of lobster 18 mm. The 

 right cheliped of this lobster was regenerated between the molts of the fifth and sixth 

 stages. When the animal was preserved, August 17, 1893, the right regenerated cheliped was 

 slightly smaller and more translucent than the left. No rudimentary tissue out of which 

 the new limb is differentiated can be detected in the series of sections through plane of 

 fracture, x y, plane of fracture; 1, 2, 3, segments of limb. About 47 times natural size. 



Fig. 170. Internal surface of cuticle of second joint (basis) of first maxilla macerated in Bela Haller's 

 fluid, showing chitinons tubules of tegumental glands, and characteristic rosettes of what 

 appears to be calcareous matter. From male lobster 10 inches long. July 31, 1893. 140 

 times natural size. 



Fig. 171. Part of section of gastrolithic plate from female lobster with hard shell. August 10, 1893. 

 Shown in its natural position in wall of stomach, in fig. 183. Fixed in picro-sulphuiic 

 acid; stained in borax-carmine; embedded in celloidin. GP., cuticular portion of gastro- 

 lithic plate. The demarcation between the layers is not so sharp as shown in the drawing. 

 171 times natural size. 



Fig. 172. Section of left first pereiopod of lobster 9 inches long, in process of regeneration. At a a 

 mass of large disk-shaped concretions, probably of a glycogenous nature, is seen. Compare 

 figs. 121 and 122. The blackened margins of cuticle on either side of appendage repre- 

 sent the remains of clotted blood on surface of the stump. About 6 times natural size. 



Fig. 173. Section of bud of right first (crushing) cheliped of adult male lobster, showing the columnar 

 epithelium, the new cuticle, blood sinuses, and connective tissue. Fixed in picro-sul- 

 phuric acid; stained in Ehrlich-Biondi mixture; embedded in celloidin. August 9, 1892. 

 47 times natural size. 



Fig. 174. Part of longitudinal section of first larva through heart (-EY.) and right rudimentary repro- 

 ductive organ (or), cutting also intestine (in) and gastric glands (gg). 67 times natural size. 



Plate 44. 



Fig. 175. Right fourth pereiopod of adult lobster in process of regeneration, from below. Color, 



bright coral red. Two-thirds natural size. 

 Fig. 176. Stump of right first pereiopod of adult lobster in course of regeneration, from below. Bud 



and surface of scar dull white. August 9, 1892. Two-thirds natural size. 

 Fig. 177. Surface view of membrane between old and new shells of molting lobster. This membrane 



is conspicuous at the time of shedding. It is noncellular, but is marked by the cell 



impressions of the chitinogenous epithelium. 733 times natural size. 

 Fig. 178. Right second pereiopod of adult male in process of regeneration, from below. New append- 

 age reddish, tinged with blue at the joints. August 4, 1892. Two-thirds natural size. 

 Fig. 179. Left second antenna of adult lobster in process of regeneration, from above. June 30, 1892. 



Two-thirds natural size. 

 Fig. 180. Antennas of the Isopod, Ligea oceanica, from above; that of the left side in the course of 



regeneration. Beaufort, North Carolina, June, 1885. 4.7 times natural size. 

 Fig. 181. Regenerating left antenna of the-same, showing the new flagellum inclosed in the exoskeleton 



of the joint, which serves as a brood pouch. 16 times natural size. 

 Fig. 182. Left first cheliped of adult lobster in process of regeneration, seen from the inner and 



anterior side. Color, bright red, bluish at joints; cuticle thrown into thin creases. 



Longitudinal axis of body in direction of arrow. 5.3 times natural size. 

 Fig. 183. Profile view of masticatory stomach of lobster, showing gastrolithic plate, for the structure 



of which see fig. 171, plate 43. Lobster with hard shell, approaching the molting time 



August 10, 1893. Two-thirds natural size. 



