64 OPISTHOBRANCHIATA OF BRAZIL 



('97, 'pSb) has given of these forms. Its lack of agreement 

 with Pleurobranchus patagonicus d'Orbigny, the only recorded 

 species from the east coast of South America, is equally clear from 

 Bergh's study of the anatomy of that species ('pSa). Nor does 

 it agree satisfactorily with the Antillean Pleurobranchus lacteus 

 of Ball and Simpson ('99, p. 367) in external characters nor in 

 shell. An anatomical study of the latter species is much to be 

 desired, however, before certainty can be assured. In the mean- 

 time I must consider the present form a new species and have 

 much pleasure in dedicating it to Professor Alexander Agassiz 

 of Harvard University. 



Type No. 145, Invertebrate Series, Leland Stanford Junior 

 University Zoological Museum. 



