LIVING BlIACIIIorODA. 379 



PLATE 41. 

 Life attitudes of Glottidia pyramidnta. 



Fig. 1 to 10. Varioas attitude.s in tlie .sand. 



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

 Fig. 11. Anterior portion projecting above tlie sand with a pile of sand in front. 

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



Fi". 13. Eight individuals attached to bottom of bowl by rude sand burrows ; compare with similar group of Liiuinlii 

 Ippidnla (40: 11). 



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



Figs. 15 and l(i. Injured peduncle with inner tube partially withdrawn from outer slieath. 



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



Fig. 20 to 30. Portions of peduncle broken away, with globular mas.ses of .sand at end. 



Fig. 31 to 33. Various attitudes. 



PLATE 42. 



Doreal and ventral shells of various forms. 



Figs. 1 and 2. Ghtttidia pi/nniiidnfa, 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 life sliowing extent of individual variation. 



Fig. 6. Appearance of .sliells when dried. 



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



Fig. 9 to 13. Discinisca lumdlnsa. 



Fig. 9. Orbicular nucleus. 



Fig. 9rt. Polygonal structure of shell. 



Fig. 96. 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 17«.) 



Fig. 17a. Dorsal view of ventral shell. 



PLATE 43. 



Peduncles of Lingula, Glottidia, Discinisca, and Terebratulina. 

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



Fig. 4 to 13. Glottidia pyramidnta. 

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

 Fig. 5. Portion of peduncle. 



