34 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.49. 



August 14, 1851, the first part of the catalogue appeared m June, 

 1852, and the last part of the report upon the 516 species was printed 

 in July of the same year, 1 1 months after the arrival of the collection 

 at Amherst. 



In this paper Professor Adams describes the following species 

 under the genus Rissoa which belong to Rissoina: 



Rissoa clandestina, p. 401. 



Rissoa firmata, p. 401. 



Rissoa fortis, p. 402. 



Rissoa janus, p. 403. 



Rissoa scalariformis, p. 404. 

 The last is a young specimen of Rissoina firmata. Here also the fol- 

 lowing shells are described as Rissoa: 



Rissoa infrequens, p. 403, which is a Pliciscala. 



Rissoa notahilis, p. 404, which is an Odostomia. 



Rissoa incons'picua, p. 402, which is also an Odostomia. 

 Later Dr. Philip P. Carpenter reported upon a collection of shells 

 made during 1848-1850 by Frederick Reigen, a Belgian gentleman, at 

 Mazatlan. His report, Catalogue of the Collection of Mazatlan 

 Shells in the British Museum, was published in parts during the 

 years 1855-1857, the part dealing with our genus appearmg in 1856. 

 Only two species are mentioned: 



Rissoina stricta Menke, and 



Rissoina woodwardii Carpenter, 

 the last being new.^ 



In 1860 O. A. L. Morch, in his Beitrage zur MoUuskenfauna Central 

 Amerikas, a paper based upon shells collected by Dr. A. S. Oersted, 

 lists the following members of the genus Rissoina:- 



Rissoina woodwardi Carpenter, from Puntarenas. 



Rissoina inca D'Orbigny, from Sonsonate. 



Rissoina scalariformis, C. B. Adams, no specific locality 

 mentioned. 



Rissoina effusa Morch, no specific locality mentioned. 



Rissoina contabulata Morch, Sonsonate. 

 The last two being additions to the Rissoina fauna of the West Coast 

 of America. 



In 1864 Dr. Philip P. Carpenter briefly described Rissoina inter- 

 fossa on page 656 of his Supplementary Report on the Present State 

 of our Knowledge with Regard to the Mollusca of the West Coast of 

 America.^ This he diagnosed more fuUy two years later on page 217 

 of his paper, Descriptions of New Marine Shells from the Coast of 

 California.* Tliis species has since been referred to the genus Bit- 



1 Cat. Mazat. Shells, 1856, p. 357. 



2 Malak. Blat., vol. 7, ISOO, pp. 67-T8. 



3 Kept. Brit. Ass. Adv. Sci. for 1863. 



< Proc. Cal. Acad. Nat. Sci., 1866, vol. 3. 



