1. Sximniary. 



Tlie result of my viovk on Teredo may be siirimarized as 

 follows: T;ie larva of Toreclo is a typical f roo-s'iVinuninn 

 marine Lamellibranch larva. Tho vriiole veliun is suddenly 

 cast off and eaten, soon after the attachment of the larva. 

 After tlie loss of the velum the younc Teredo is a typical 

 small bivalve. The loss of the velum in Teredo and in Os- 

 trea (which I have also observed) , indicates that the for- 

 mation of the palps in Lamellibranchs has no connection 

 with the velum. A byssus apparatus is present in the new- 

 ly-attached larva. It is functional for but a few hours. 

 The position and relations of the sheath of the crystal- 

 line style in the larva indicate that this structure, in 

 the more highly specialized Lamellibranchs, is liomologous 

 with the posterior half of the stomach in forms like Yol- 

 dia and Ilucula. The pleural ganglion of the larva is sep- 

 arate from the cerebral. 



The transformation of the Teredo larva into the 

 small "Ship-worm" is so rapid as to arioiint to a metamor- 

 phosis. Almost the whole organization is involved - sheH^ 

 ;..antle, foot, alimentary canal. The posterior adductor is 

 the effective agent iii I'orming the burrow, and tho shell 



