27 



nigris; dorsi alarumque plumis intense cinereis, nigra marginU' 

 tis, pedibus nigris. 

 Long. tot. 23unc. ; rostri, 2| ; ala, 9^; cauda, 7^; tarsi, 1^. 



Orpheus trifasciatus. Orph. vertice, nucha, et dorso nigres- 

 centibus; uropygio rufopallide lavato; alis nigrescentibus tectri- 

 cibus not a albescente terminali, fascias tres transversas facienti- 

 bus rectricibus caudce duabus intermediis nigrescentibus, reliquis 

 ad apicem pallidioribus ; plumis auricularibus strigd superci- 

 liari, guld, et corpore svhtus albis, lateribus notis guttisque 

 fuscis ornatis ; rostro pedibusqtce nigris. 



Long. tot. lOf unc. ; rostri, If ; alee. 5 ; cauda, 5^ ; tarsi, 1|. 



Orphkus melanotis. Orph. vertice, nuc/id, dorsoque pallidl fus- 

 cis ; plumis capitis et dorsi ad medium colore saturatiore ; alis 

 intense fuscis singulis, plumis ad marginem pallidioribus, seconda- 

 riis. tectricibusque majoribus notd albd terminali, fascias duas 

 transversas facientibus ; cauda rectricibus nigrescenti-fuscis ad 

 apicem albis, loro, plumisque auricularibus nigrescenti-fuscis ; 

 laterum plumis notd fused centrali, abdomine albo ; rostro pedi- 

 busque nigris. 



Long. tot. 9i unc. ; rostri, 1^ ; alee, 4^ ; caud<e, 4^ ; tarsi. If. 



Orpheus parvulus. Orph. vertice, nucha cauddque intense fuscis, 

 hujus rectricibus ad apicem albo notatis; alis fuscis secondariis 

 tectricibusque notd albd apicali fascias duas transversas facien- 

 tibus ; loro, plumisque auricularibus nigrescentibus, guld, colli 

 lateribus pectore, et abdomine albescentibus ; plumis laterum notis 

 fuscis per medium longitudinaliter excurrentibus. 



Long. tot. 8^ unc. ; rostri, 1 ; alee, 3|; caiidcB, 3f ; tarsi, \\. 



Mr. Waterhouse resumed the exhibition of the small Rodents, 

 belonging to the collection presented by Mr, Darwin to the Society. 

 Among them were three species allied to the genus Mus, but offering 

 some slight modification, not only in the external form, but in the 

 structure of the teeth. They have the fur soft and silky ; the head 

 large, and the fore legs very small and delicate ; the tarsus mode- 

 rately long and bare beneath ; in the number and proportion of the 

 toes they agree with the true rats ; the tail is moderately long, and 

 more thickly clothed with hair than in the typical rats. The ears 

 are large, and clothed with hair. Like the true rats, they have 

 twelve rooted molars ; the folds of enamel, however, penetrate 

 more deeply into the body of each tooth, and enter in such a way 

 that the crowns of the teeth are divided into transverse and some- 

 what lozenge-shaped lobes, or in some instances into lobes of a 

 triangular form. In the front molar of the upper jaw the enamel 

 enters the body of the tooth twice, both on the outer and inner 

 sides ; and in the second and posterior molars, both of the upper 

 and under jaws, the enamel penetrates but once externally and in- 



