1918. | A Double Monstrosity in the Chick. 337 
EXPLANATION OF PLATES III—IV. 
An Abnormal Chick. 
Fie. 1.—A and B. ‘Two different views of the animal with 
the ey and skin intact. 
ce. 2.—A and B. Two different views of the same, with 
the Fine al removed. 
Fie. 3.—Ventral view of the sternum, ribs, and a portion 
of the vertebral column of both the indivi dua Is. 
a = keel or carina ee ; Aes = sternum ; c = furcula; d= cor ce a e= 
: = ene ri uncini 
= 4 apheae ; exte ho rocess Ps 
column of the right individual; k’= vertebral column of t e left hg 
dual; 7 and l’= vertebral ribs of the — and fais individaal, lying 
the dorsal side of the body of the animal, and s by dotted lines. 
Fie. 4.—The digestive canal, with me Lee cut open 
_ and Portions of the ileum remo ved, seen from the ventral side. 
= gullet; b= si ; ¢ = proventriculus; d= arene: of the gizzard ; 
e= Ade enum; {= region of ileum; g = middle region of ileum, 
and the point of feraner <j into the right and left portion of ileum; h = 
the ileum of the left indi vidual ; h’= the ileum of the right individual 
*= rectum of the left indivi dual ; j = rectum of the right pop idual: & 
and k’= openi ngs of the rie: of both the individuals into c 
Fig. 5.—The heart and chief blood vessels, Sauer aspect. 
c= ventricle ; b = left auricle; c= <—~ auricle ; d = left pulmonary 
e 
aortic arch ; e’= left aortic arch ; e” = right aortic arch ; 
f = lett pre-caval vein; /’= right mehseitor vein; g = left jugular vein; 
9 =right jugular vein; A = left dorsa ; h’= left verteb ry; 
+= su en arteries of the left indivi, a se vig Lominate 
Ty; 1 = left innominate artery; 7 =left carotid artery; 7’= right 
carotid artery k = subclavian arteries a the right individu ate v= right 
vertebral arte ry ; /= sinus venosus; m = vitelline vein; ee = left vi ce 
artery ; n’= right vitelline apery 25 right dorsal aorta; y = y 
shewn much smaller than 
Fie. 6.—The ty duputea forwards to show the sinus 
Yenosus, ventral aspect 
_4=left ventricle: 6 = right ventricle ; c= left sgt em = right 
Suricle; ¢ — eft pre-caval vein; gee right pre-caval v s 
venosus; fh = vitelline vein; i= t post-caval vein ; bart right post- 
caval tee 
7.—Diagrammatic transverse section through the 
body oe the monster, to show the position of the two sterni, 
ribs, and vertebral column of both the individuals. 
5 — 7 — sternum (situated dorsally); a’ mbar (situated ventrally) ; 
= vertebral column of the oe jeidlivichoad ; = vertebral column of the 
Tight individual ; ¢ = sternal rib; d = ve stcebeakits 
POPP PA am 
