382 EDWARD S. MORSE ON 



Fig. 3. Longitudinal section. 



Fig. 4. Bend of intestine and peduncular canal. 



Fig. 5. Peduncular canal. 



Fig. 6. Stomach with gastro- and ilio-parietal bands. 



Fig. 7. D. Stella, showing head and brachia. 



PLATE 50. 



Details of alimentary tract of various forms. 

 Fig. 1 to 10. Glottidia pyramidata. 

 Figs. 1 and 2. Longitudinal sections of moutli parts. 



Figs. 3 and 4. Mouth and brachia from ventral side showing mobility of the lips. 

 Fig. 6. Dorsal view of pharyngeal region. 



Fig. 6. Roof of pharynx from inside, showing triturating ridges. 



Figs. 7 and 8. Ventral and dorsal views respectively of stomach and portion of intestine. 

 Fig. 9. Transverse section of intestine showing attachment of ilio-parietal band. 

 Fig. 10. Anus. 



Figs. 11 and 12. Rectum and anus of L. lepidula. 

 Fig. 13. Portion of right coelomic wall of D. lamellosa showing anus. 

 Figs. 14 and 15. Gut of 1). lamellosa from an early stage. 

 Fig. 16. Section of gut of T. septentrionalis. 



Fig. 17. Digestive tract of H. psittacea, with stomachal glands removed. 

 Fig. 18. Anterior portion of digestive tract of H. psittacea showing stomachal glands. 



PLATE 51. 

 Stomachal glands, sense organs and nerves of various forms. 

 The following figures represent a single coecum, or a cluster of coeca of the stomachal glands, unless otherwise mentioned. 

 Fig. 1. G. pyramidata. 

 Fig. 2. L. anatina. 



Figs. 3, 4, and 5. Showing the entire cluster on one or both sides of the stomach of young D. lamellosa. 

 Fig. 6. D. Stella. 



Figs. 7 and 8. T. septentrionalis. 

 Fig. 9. T. coreanica. 

 Figs. 10 and 11. H. psittacea, young. 

 Fig. 12. n. psittacea, adult. 

 Fig. 13. Dallina grayii. 



Fig. 14. Longitudinal section of mouth parts of G. "pyramidata, showing infra-oesophageal ganglion and nerve. 

 Fig. 15. Pallial folds with pigmentation, supposed to be sensitive to light, idem. 

 Fig. 16. Greatly enlarged view of pigmentation of one fold. 

 Figs. 17 and 18. Nerve and otocyst of L. lepidula. 



Fig. 19. Nerve with nerve twigs and section of nerve of G. pT/ramid<ita . 

 Fig. 20. Otocyst of L. anatina. 



PLATE 52. 

 Nerves and otlier details of various forms. 

 Figs. 1 and 2. Otocyst and surrounding parts of L. lepidula. 

 Fig. .". Infra-oesophageal ganglia of D. stellii. 



