TWINNING IN DASYPUS NOVEMCINCTUS 27 



Fernandez" published an account of several embryonic 

 stages of the Mulita {D. hybridus) taken in the Argentine 

 Republic; and Newman and Patterson^ pubhshed a 

 preliminary report, based iipon some advanced embry- 

 onic stages, of the conditions existing in D. novemcitictus 

 Texanus — the Texas armadillo. Since the conditions 

 in the two species are essentially similar and since much 

 more has been published about the latter species, the 

 main account of polyembryony in the armadillos will be 

 based upon conditions worked out for the Texas species. 



ECOLOGY AND HABITS OF THE TEXAS ARMADILLO, 



Dasypus novemcinctus Texanus 



The average adult armadillo (see frontispiece)' is 

 an animal with a body length of about eighteen inches, 

 with a long, sharp nose, mulish ears, and a pointed 

 tapering tail nearly as long as the head and body 

 together. The most striking structural feature is the 

 armor, which consists of a carapace composed of a 

 solid, scapular shield anteriorly, a pelvic shield poste- 

 riorly, and a median banded region, consisting of nine 

 movable bands of armor. There is a cephalic shield on 

 top of the head and the tail is composed of rings of armor 

 plate separated by armorless rings of soft skin. The 



' M. Fernandez, Morpholog. Jahrb., Bd. 39 (1909). 



' H. H. Newman and J. T. Patterson, Biological Bulletin, XVII, 

 No. 3 (1909). 



' This illustration, painted by Mr. Kenji Toda from photographs 

 of living animals, is the only really good figure of an adult Dasypus 

 of any species that has been published. The usual figures are from 

 photographs of stuffed specimens in entirely incorrect attitudes and 

 in unnatural surroundings. This picture is in every respect an 

 adequate representation of this interesting animal. 



