LIVING BRACHIOPODA. 379 



PLATE 41. 



Life attitudes of Glottidia pyraiiiidata. 



Fig. 1 to 10. Various attitudes in tlie sand. 



Fig. 3. With peduncle broken away, burying itself liead first in the sand. 

 Fig. 11. Anterior portion projecting above the sand witli a pile of sand in front. 

 Fig. 12. With peduncle broken away, burying itself sidewise. 



Fig. 13. Eight individuals attached to bottom of bowl by rude sand burrows ; compare with similar group of Liagnla 

 lepidula (40: 11). 



Fig. 14. With ca.se of sand around posterior end of body. 



Figs. 15 and 1(>. Injured peduncle with inner tube partially withdrawn from outer sheath. 



Fig. 17 to 25, Various attitudes, some with sand tube preserved. 



Fig. 26 to 30. Portions of peduncle broken away, with globular masses of sand at end. 



Fig. 31 to 33. Various attitudes. 



PLATE 42. 



Dorsal and ventral shells of various forms. 



Figs. 1 and 2. Glottidia pyramidata, dorsal and ventral shells. 



Fig. 3 to 8. Lingula lepidula. 



Fig. 3. Ventral view of posterior end showing protegulum and portion of peduncle. 



Fig. 4. Posterior end, ventral view. Arrows indicate direction of circulation . 



Fig. 5. Outlines of shells in lite showing extent of individual variation. 



Fig. 6. Appearance of shells when dried. 



Figs. 7 and 8. Posterior end of dorsal and ventral shells. 



Fig. 9 to 13. Discinisca lamellosa. 

 Fig. 9. Orbicular nucleus. 

 Fig. 9a. Polygonal structure of shell. 

 Fig. 95. Fracture of shell margin. 

 Fig. 10 to 13. Dorsal and ventral shells showing protegulum stage. 



Fig. 14 to 17. Discinisca Stella. 



Fig. 14. Portion of ventral shell showing radiating ridges. 



Fig. 15. Greatly enlarged view of two ridges. 



Fig. 16. Nucleus of ventral shell. 



Fig. 17. Longitudinal section. (The lower of the two figures should have been lettered 17a.) 



Fig. 17a. Dorsal view of ventral shell. 



PLATE 43. 



Peduncles of Lingula, Glottidia, Discinisca, and Terebratulina. 

 Fig. 1 to 3. Lingula lepidula, showing severed ends of peduncle. 



Fig. 4 to 13. Glottidia pyramidata. 

 Fig. 4. Showing withdrawal of inner tube and muscular tube from end of outer sheath. 

 Fig. 5. Portion of peduncle. 



