LIVING BKACHIOPODA. 383 



■Fig. 4. Hight half o£ coeloiuic cavity of D. laiiuUuna, »liowiiig oblicjue nerve and its terniinalinn in the posterior ocolusor 

 iniisole; in this figure the retractor brachia muscle is turned up to expose coui'se of nerve. 



Fig. 5. Ganglion of posterior occlusor muscle, greatly enlarged, idem. 



Fig. 6. Infra-oesophageal ganglia of T. cureaiiica. 



Fig. 7. Portion of pallium .showing gill ampullae, .setae, etc., of G. pyramidaln. 



Fig. 7(1. Natural size of object s'.iowia;^ region from which fig. 7 is drawn. 

 Fig. 8 to 11. Color markings of t'.ie p.iUinin of various species of LiiiguUdas. The .setae are purpo.seiy omitted in the.se 



figures except in fig. 9. 



Fig. 8. G. pyramidata. 



Fig. 9. L. lepidula. 



Fig. 10. L. anatina. 



Fig. 11. Lingula, .species unknown, from Naga.saki. 



I'LATE 53. 



Details of circulation in Gliittiilin piji-iiinhhilii and Linguhi lepidula. Arrows indicate diri-ction of currents. 



Fig. 1 to 7. GloUldia pyramidata. 

 Fig. 1. Dur.sal view .showing main and lateral pallial sinuses with lacunae, and coelomic and median sinn.ses. 

 Fig. 2. Portion of pallium .showing three rows of gill ampullae. 

 Fig. 3. A single row of gill ampullae, greatly enlarged. 



Figs. 4, 5, and 6. Transverse sections throu'^h lacune of pallinm. Appearance of polygonal cells of endothelium. 

 Fig. 7. [Showing regions of above sections. 



Fig. 8 to 12. Lingula lepidula. 

 Fig. 8. Dorsal view. The left brachium is shown with cirri removed. 

 Figs. 9 and 10. Opening of main pallial sinus and adjacent parts. 



Fig. 11. A portion of main pallial sinus .showing diverticular lacunae; these appear (juite circular in section. 

 Fig. 12. A single lacune, in section, greatly enlarged. In the drawing of Lingula, at one side, is indicated the region 

 from which Hgs. 11 and 12 were taken. 



Fig. 13. Lateral sinus of G. pyramidata; t'.iis is ligiired on the plate laterally. 



PLATE 64. 



Circulation, blood corpuscles and uephridia of various forms. 

 Fig. 1. Side view of G. pyramidata, .showing result of injection of red flnid through peduncular cavity. 

 Fig. 2. Doreal view of .same. It will be .seen that in this experiment the fluid tilled the median sinus and the minute 

 vessels of the perivisceral lining, but did not enter the coelomic cavity or the sinuses of the pallium. 

 Fig. 3. Blood corpuscles of G. pyramidata. 

 Fig. 4. Same of L. lepidula. 

 Fig. 5. Same of L. anatina. 

 Fig. 0. Same of D. lamellosa. 

 Fig. 7. Same of T. cureanica. 

 Fig. 8. Same of T. scptentriunalis. 

 Fig. 9. Left nephridium of G. pyramidata. 



F'ig. 10. Greatly enlarged view (jf pnrtinn of ncphnistuiue, idem. 

 Figs. 11, 12, and 13. Nephrostome of L. lepidula. 

 Fig. 14. Nephrostome from the under side, idem. 

 Fig. 14([. <.)ne fold of nephrostome greatly enlarged showing ciliary ridge, idem. 



