104 



about one day, front view. The first row oi' teeth, apophyses 

 and pivotal '-.'.lobs have been fori'ied. '!" ^-i ..i i ,^,^3 at both 

 ends. X 220, 



.Fie. 15. Left shell valve of specimen about 1 mm, lon,^. 

 Oblique view. Tlie larval shell still shown, x 220, 



Fig, 10. Left shell-valve of specimen 5 nim. lon^. x 45. 



Fig, 17. Left shell-valve of adult, x 15. 



Fig, IS. Front view of shell of adult. x 15. 



Fig. 19. Internal view of i-ight valve, x 15. 



Fig, 20, Left palette of specimen 5 mm, long, x 140. 



Figs. 21 and 22, Diagrams of the posterior end of body 

 of adult, left side, to shovr the arrangement of the siphons 

 and palettes^ and their muscles. In fig. 21 the siphons are 

 represented as extended, the palettes as retracted; in fig, 

 22, the siphons are represented as contracted, the palettes 

 as protracted. 



Fig, 23. Dorsal gland of the posterior part of the man- 

 tle. Section of whole gland of specimen 5 mm. long. The 

 letters are j laced in the epibranchial cavity. x 850. 



Fig. 24, Sagittal section of a newly-attached larva. 

 The very large glands of the foot occupy a large part of the 

 mass of the latter. A large quantity of material derived 

 from these glands lies adjacent to tlie byssus gland. The 



