184 H. H. NEWMAN AND J. THOS. PATTERSON. 



areas, but each partition passes through the middle of an area 

 and thus intersects the apices of the proximal and distal scallops 

 (see Fig. i). The four partitions, furthermore, do not meet 

 within the cavity in a line corresponding to the polar axis of the 

 vesicle, but are fused in such a way that the cavities containing 

 the embryos numbered I and 3 meet on their inner faces, while 

 those containing 2 and 4 do not (see Fig. 2). 



In a note in the current issue of Science (April 30) Professor 

 H. H. Lane gives a brief account of placentation in the armadillo 

 that differs in a number of particulars from the above. The dis- 

 crepancies might be explained by the fact that Lane's account 

 rests upon observations made upon a single deciduate placenta, 

 taken after the birth of a litter. In addition to its incompleteness, 

 his account differs from that offered here chiefly in locating the 

 points of attachment of two of the umbilical cords on each of 

 the large "disc-shaped areas," and none on the smaller areas. 

 This condition is certainly not found in any of our material. 

 A more fundamental difference between the two accounts lies 

 in the interpretation of the condition of the chorion, Lane hold- 

 ing an opinion completely out of accord with the facts here 

 presented, that the definitive chorion is the product of a complete 

 fusion of four chorionic vesicles into one. 



The unique interest of this case lies in the fact that the four 

 embryos of a given set are not only invariably of the same sex, 

 but are practically identical in many other respects. Measure- 

 ments of the body and head lengths showed no essential differences 

 between the individuals of a set of quadruplets, but a more search- 

 ing comparison, consisting of carefully confirmed counts of the 

 total number of plates in the nine bands of the armor, revealed, 

 as one might expect, slight departures from complete identity. 

 The results obtained from the examination of two sets will serve 

 to indicate the small range of these departures. 



Set A (Females). Set B (Males). 



No. 1 556 (-4 I) plates 1 No. 1 571 (+2) plates 



No. 2 555(+2) " No. 2 573 (+i) " 



No. 3 553 (+ 2 ) " No. 3 569 



No. 4 551 ( + 4) " No. 4 568 " 



1 The numbers enclosed in parentheses refer to certain rudimentary plates that are 

 more or less united with other plates. It is impossible to tell in the embryos whether 



