On new Mammals from Bolivia. 277 



form of an elliptical projection, and the posterior area is a 

 flat expansion. Both, especially the anterior projection, are 

 quite sensitive to mechanical stimulation. They are both 

 entirely distinct from the organ of special sense described by- 

 Brooks (1). Their special functions remain to be determined. 

 My thanks are due to Dr. W. K. Brooks, who has directed 

 this work, and I wish publicly to acknowledge ray indebted- 

 ness to my wife, who has materially aided me in securing, 

 tending, and preserving specimens. 



Zoological Laboratory, Johns Hopkins University, 

 Baltimore, May 1, 1897. 



Literature cited. 



1. Brooks. — "An Organ of Special Sense in the Lamellibranchiate 



Genus Yoldia.''' Proc. Am. Assoc. Adv. Sci. 1874. 



2. Kellogg. — " A Contribution to our Knowledge of Lamellibranchiate 



Mollusks." Bli11.,U.S. Fish Com. 1890. 



3. KowALEvsKY. — " Etude sur rembryogenie du Bentale." Ann. du 



Mus^e d'hist. nat. de Marseille, Zool. tome i. 1883. 



4. liACAZE-DuTHiERS. — " Histoire de I'organisation et du d^veloppe- 



ment du Dentale." Ann. des Sci. nat. iv. s6r. tome vii. 1857. 



5. MiTSUKUm. — " On the Structure and Significance of some Aberrant 



Forms of Lamellibranchiate GiUs." Quart. Journ. Micr. Sci. 

 vol. xxi. 1881. 



6. Pelsneb. — " Contribution a I'etude des Lamellibranches." Archives 



de Biol, tome xi. 1891. 



7. Prxjvot. — "Sur le d6veloppement d'un Solenogastre." Oomptes 



Rend., Paris, tome cxi. 1890. 



8. Sigerfoos. — "Notes on the Organization of the Larva and the 



Post-larval Development of Ship-worms." Johns Hopkins Uni- 

 versity Circulars, vol. xv. no. 126. 1896. Ann. & Mag. Nat. 

 Hist. vol. xviii. 1896. 



9. Wilson. — " Origin of the Mesoblast-bands in Annelids." Journ. of 



Morph. vol. iv. no. 2. 1890. 



XLV. — On some new Mammals from the Neighbourhood of 

 Mount Sahama, Bolivia. By Oldfield Thomas. 



The British Museum has purchased from Mr. Gustav Garlepp 

 a small series of mammals obtained by him at Esperanza, a 

 " tambo " in the neighbourhood of Mount Sahama, Bolivia, 

 while collecting birds for Count von Berlepsch. The speci- 

 mens prove to be of considerable interest, as there are among 

 them examples of no less than five new species, one of these 

 representing a new genus. 



Mr. Garlepp informs me that " the mammals were all 

 taken at an altitude of 4000 metres in the ' Puna ' region — 

 that is to say, on the high plateau between the Coast 



