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THE AMERICAN NATURALIST [Vol. XLIII 



roof, cutting off the space for the two upper trays, and omitting 

 the partition from this space. When packed with nests of the 

 Fielde type the whole outfit weighed about twenty-six pounds; 

 but when packed with my aluminum nests, only about half as 

 much, the weight of the case alone being about six pounds. 



A strong leather shawl-strap, with stout handle, was used in 

 carrying the case. 



PAPEKS CITED 



Fielde, Adele M., "Portable Ant-nests," Biol. Bull, Vol. II, No. 2, 1900, 

 pp. 81-85, 3 figs. 



Fielde, Adele M., "Portable Ant-nests," Biol. Bull., Vol. VII, No. 4, 1904, 

 pp. 215-222, figs. 1-3. 



Edith N. Buckingham. 



Boston, Mass. 



COMPARISON OP CvEKOLESTES WITH POLYPRO- 

 TODONTA AND DIPROTODONTA 



Caenolestes has been described by Mr. Oldfield Thomas (1895) 

 who placed it in the family Epanorthidae of the suborder Dipro- 

 todonta, which includes several fossil forms described by 

 Ameghino. Sinclair, however, in the "Report of the Princeton 

 Patagonian Expedition" (1901-6) gives the name Camolestidae 

 to these small Santa Cruz Diprotodonts, from the genus Caeno- 

 lestes, which, although a modern form, is more primitive than 

 any of these fossils in regard to the diprotodont character of 

 the teeth. 



In view of the phyletic interest attaching to this form, as 

 perhaps the starting point for the evolution of diprotodont tooth 

 structure, it was considered advisable to make more completely 

 detailed drawings of the skull than had before been done, in 

 respect principally to sutures and foramina, and to compare 

 skull and other characters with types of Polyprotodonta and 

 Diprotodonta. 



The skull from which the accompanying drawings were made 

 is the specimen which Sinclair figured in his report, loaned to 

 me through the courtesy of Dr. J. A. Allen, from the collection 

 of the American Museum of Natural History. I am indebted 

 also to Mr. W. K. Gregory, of the museum, for many helpful 

 suggestions during the course of the work. 



Among the general marsupial characters of the skull of Caeno- 

 lestes may be mentioned the following: absence of pituitary 



