MUSEUM OF COMPARATIVE ZOOLOGY. 45 



openings of the ducts. The position of the brachia and labia with regard 

 to the esophagus, and of the heart, are shown. 



4. Diagram of Cistella var. lutea, representing the animal in the shell, 

 with the long brachial cirrhi behind the oral groove turned back to show 

 the groove and position of the mouth. The other cirrhi are curled up in 

 their natural position. 



5. Side view of the stomach, intestine, and hepatic lobules of the same 

 species, with a section of the oesophagus, showing the position of the cirrhi 

 and labia. The heart is seen below, just behind the hepatic lobules. 



6. Same, with the lobules removed, showing the openings of the ducts, 

 the position of the heart, and the shape of the mesentery in which the 

 intestine is suspended. 



7 Genitalia of the same, showing how they are suspended from a rib- 

 bon-like lamella, with the ova in various stages upon the edge of it. 



8. Rudimentary folds and simple opening of the oviducts of the same. 



9. Diagram of the pallial sinuses of Waldheimia sepligera, with the 

 ovaria, from a dry specimen. The haemal lobe is above. 



Cambridge, May, 1871. 



