POLYCH^TA SEDENTARIA OF THE FIRTH OF FORTH. 683 



Fig. 7. Scoloplos armiger, anterior end, dorsal surface. 7 a, same, lateral surface ; 7 b, posterior end, 

 dorsal surface ; 7 c, transverse section, middle region ; 7 d, 7 e, 7 f, 7 G, chaetae. 



Fig. 8. Theodisca mammillata, anterior end, lateral surface. For remaining figs, of this species 

 see PI. XL. 



Fig. 9. Cirratulus cirratus, anterior end, dorsal surface. 9 a, same, ventral surface ; 9 B, same, 

 lateral surface. 



Fig. 1 0. Cirratulus tentaculatus, anterior end, dorsal surface. 10 a, same, lateral surface. 



Plate XXXIX. 



Fig. 9 c. Branchiaof C. cirratus, optical longitudinal section, fresh — bl, bl, the two main blood-vessels ; tr, 

 tr, transverse connecting small vessels. 9 d, tran verse section of branchia — bl, bl, as before ; 

 n, n, nerves ; c, c, coelomic cavity. 9 e, tentacle, optical longitudinal section, fresh — bl, single 

 blood-vessel; g, longitudinal groove. 9 f, transverse section of tentacle — bl, blood-vessel ; 

 c, c, coelomic cavity; g, longitudinal groove; n, n, nerves. 9 G, anterior end showing anterior 

 pair of nephridia ; 9 h, nephridium. 



Fig. 10 b. Chaetae of Cirratulus tentaculatus. 



Fig. 11. Chcetozone setosa. 



Fig. 1 2. Dodecaceria concharum, anterior end. 



Fig. 1 3. Arenicola marina. 13 b, 13 c, chaeta and uncinus. 



Plate XL. 



Fig 13 d. Portion of immature ovary of Arenicola marina, fresh, Zeiss DD, Oc. 2 ; 13e, immature 

 ova from body-cavity, February, fresh, Zeiss DD, Oc. 2 ; 1 3 f, sperm polyplast from body- 

 cavity, same time, same power, fresh. 



Fig. 14 a. Embryo probably of Scoloplos armiger, early stage, taken from pear-shaped gelatinous 

 cocoon, Feb. 3, 1887, Zeiss CC, Oc. 3 ; 14 b, later stage, Feb. 4th; 14 c, same stage as 

 previous figure, optical section ; 1 4 D, more advanced, some days after hatching ; 1 4 E, 

 later stage, chaetae commencing to appear; 14f, latest stage observed. 



Fig. 8 a. Theodisca mammillata, anterior end, dorsal surface. 8 b, posterior end of same species ; 

 8 c, capillary chaeta ; 8 d, 8 e, uncini of same. 



Plate XLI. 



Fig. 15. Ammotrypane aulogastra, anterior end, dorsal surface. 15 a, anterior end, lateral surface — 



a, soft proboscis ; b, cephalic organ. 15 b, posterior end, lateral surface ; 15 c, parapodium 



and branchia as seen in a transverse section. 

 Fig. 16. Ophelia limacina, entire specimen, lateral surface. 

 Fig. 1 7. Sabellaria spinulosa, entire specimen, lateral surface. 17 a, anterior end, ventral surface, 



highly magnified; 17b, anterior end, lateral surface; 17c, paleae of the operculum; 



17 D, chaita of neuropodium, and imcinus of the notopodium. 



Plate XLII. 



Fig. 1 5 d. Opalina from the intestine of Ammotrypane aulogastra. 



Fig. 18. Eumenia crassa, lateral surface. 18 a, anterior parapodium, with branchia; 18b, posterior 



parapodium of same. 

 Fig. 19. Lepobranchus Jeffreysi, lateral view. 

 Fig. 20. Pectinaria Belgica, lateral surface. 20 a, anterior end, dorsal surface ; 20 b, anterior 



end, ventral surface; 20 c, capillary chaeta; 20 d, uncinus. 20 e, specimen dissected 



from ventral surface — w. I, white gland ; ne, nephridia. 

 Fig. 21. Ampharete gracilis, lateral view. 21a, head, anterior surface; 21b, capillary chaeta; 



21c, uncinus. 

 Fig. 22, Melinna cristata, lateral view. 22 a, anterior end, dorsal surface, magnified; 22 b, anterior 



end, ventral surface ; 22 c, dorsal hook, magnified ; 22 d, capillary chaeta; 22 e, uncinus ; 



22 f, chaeta. 



Plate XLIII. 



Fig. 23. Amphitrite Johnstoni, lateral view. 23a, capillary chaeta; 23b, uncinus. 23 c, 

 specimen opened from dorsal surface — ht, heart; ne, nephridia; int, intestine. 23d, 

 nephridium separated, magnified. 



VOL. XXXIII. PART III. 5 G 



