THE OPISTHOBRANCHIATE MOLLUSCA OF 



THE BRANNER-AGASSIZ EXPEDITION 



TO BRAZIL.* 



During the explorations of the Branner-Agassiz expedition 

 to Brazil in 1899 a small collection of Opisthobranchiate Mollusca 

 was made by Mr. A. W. Greeley, a member of the expedition. 

 These were turned over to the writer for study, and the results 

 obtained are embodied in the present paper. The Opisthobranchs 

 of the Brazilian coast are but little known, no systematic effort 

 having been made as yet to collect and study them, and it is only 

 occasionally that reference to them is to be found in the literature 

 upon the subject. Several shell-bearing Opisthobranchs have been 

 described by various authors, but the naked members of the group 

 have received but scant attention, and Von Ihering is practically 

 the only author who has examined the Brazilian forms. His list 

 and description of six species of Nudibranchs published in 1886, 

 has remained for twenty years with but scanty additions. 



The collection made by Mr. Greeley, though but small and 

 made without any especial attention to the group, adds seven to the 

 list of species thus far known from Brazilian waters, and is an 

 indication of the results which careful and extended collecting in 

 those regions might secure. Two shell-bearing Opisthobranchs 

 were also found in the collection made by Mr. Greeley and studied 

 by Professor W. H. Dall, and are listed in his "Mollusks from the 

 Vicinity of Pernambuco," Proceedings of the Washington Acad- 

 emy of Sciences, III. 1891. p. 139-147. These are added to the 

 list given in the present paper. 



There is so little known about the structure of the Opistho- 

 branchs from this region that a somewhat detailed examination 

 of the collection in this respect has seemed warranted, especially 

 since external characters afford so meagre a basis for classifi- 

 cation in this group. Unfortunately the number of specimens 

 secured is but small, so that, in most cases, the minute anatomical 

 study was hampered by the lack of material. No notes save those 



* Other reports upon the collections made by the Branner-Agassiz Expedition 

 have appeared in Volume III of the Proceedings of the Washington Academy of 

 Sciences. 



