THE AMERICAN LOBSTER. 245 



Plate 36. 



Fig. 11(5. Section of reproductive organ of embryo near time of hatching. 513 times natural size. 



Fig. 1 IT. Section of right reproductive organ of first larva. R. O., reproductive organ. 513 times 

 natural size. 



Fig. 118. Right second antenna of an adult female lobster, overgrown with alga? (chiefly Ulva and 

 l.iiinhuiria), seen from above. Length of lobster about 10^ inches Taken from lobster 

 pound at Vinal Haven Island, Maine, August 26, 1893. Two-thirds natural size. 



Fig. 119. Oviduct and part of ovarian lobe from left side, showing a row of unextruded eggs in duct. 

 Length of female about 10 inches. External eggs in yolk segmentation. Woods Hole, 

 Massachusetts, August 3, 1894. Of?, oviduct. Two-thirds natural size. 



Fig. 120. Reproductive organs of adult male lobster from above. Duct of testis in natural position 

 on right side, dissected out on the left. Dotted lines (2 to 5) mark planes of section of 

 the vas deferens and refer to figures on plate 37. a, proximal segment; b, glandular 

 segment ; c, ductus ejaculatorius ; in, intestine ; gg, gastric gland. Two-thirds natural size. 



Fig. 121. Disk-shaped concretion, probably containing glycogen, from maxilla; cracked by pressure. 

 133 times natural size. 



Fig. 122. Large granular cell from first maxilliped, probably glycogenous in function. August 17, 1893. 

 733 times natural size. 



Fig. 123. Reproductive organs of adult female dissected out, viewed from above; ovary nearly ripe. 

 Length of lobster lOf inches. No. 77, table 20. August 21, 1890. od, oviduct. Two- 

 thirds natural size. 



Plate 37. 



Fig. 124. Transverse section of proximal end of vas deferens of adult lobster. Plane of section marked 

 "1" in fig. 120. Duct filled with sperm ; lining-epithelium consists of small Hat cells. This 

 and figs 125-128 are from the same organ and illustrate the anatomy of the different parts of 

 the male duct, sp, sperm cells ; mb, connective tissue sheath of duct. 36 times natural size. 



Fig. 125. Transverse section of vas deferens of adult lobster. Plane of section marked " 2 " in rig. 120. 

 ep, epithelial lining of duct. 36 times natural size. 



Fig. 126. Transverse section of vas deferens of adult lobster, showing thick muscular walls. Plane 

 of section marked "4" in fig. 120. emu, circular muscles; I. ma, longitudinal muscles; 

 Bl. S., blood sinus. 36 times natural size. 



Fig. 127. Part of transverse section of vas deferens, in plane marked "5" in fig. 120. bin, basement 

 membrane; emu, circular muscles; ep, epithelial lining constituting the spermatophoral 

 glands; l.mu, longitudinal muscles; mb, membranous sheath. 190 times natural size. 



Fig. 128. Part of transverse section of vas deferens through glandular portion, in plane marked "3," 

 fig. 120, showing spermatophores, contained sperm and glandular lining-epithelium. The 

 gelatinous spermatophore is a secretion of the latter, a, b, compartments of duct; /, 

 inward fold of epithelium of duct ; Sp, sperm ; Spr, inner gelatinous substance of sperma- 

 tophore. 36 times natural size. 



Fig. 129. Ripe sperm cells : b, c, from the vas deferens of an adult male and a, from the seminal 

 receptacle of a female. About 550 times natural size. 



Plate 38. 



Fig. 130. Seminal receptacle of adult female, from above. Natural size. 



Fig. 131. Ovaries of immature lobster, seen from above. Length of lobster 44 mm. (1.73 inches). 

 Length of ovary 15 mm.; diameter of lobe J mm. From No. 2, table 32. Color opaque 

 white. Oviducts, though undoubtedly present, not seen in dissection. Natural size. 



Fig. 132. Ovaries of immature lobster, seen from above. Length of lobster 74.5 mm. (2y| inches). 

 Length of ovary 41 mm. ; diameter of lobe 1 mm. From No. 98, table 20. Natural size. 



Fig. 133. Egg teased from fresh ovary shown in fig. 138. Represents relative size of ovarian eggs one 

 year older than those shown in fig. 134. 44 times natural size. 



Fig. 134. Ova teased from fresh ovary shown in fig. 136. Drawn to same scale as fig. 133. This illus- 

 trates the size at the time of egg-laying of the immature eggs which are to form the next 

 generation, and "which will be ready for extrusion two years hence. One year later they 

 attain the relative size shown in fig. 133. 44 times natural size. 



Fig. 135. Ova teased from fresh ovary shown in fig. 137. The difference in relative size between these 

 eggs and those shown in fig. 134 represents a growth of about six weeks in summer. 

 44 times natural size. 



