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II. Remarks on the Cloaca and on the Copulatory Organs of the Amniota, 
By Hans Gadow, Ph.D., M.A., Lecturer on the advanced Morphology of Vertebrata, 
and Strickland Curator in the University of Cambridge. 
Communicated by Professor M. Foster, Sec. R. S. 
Received March 11,—Read March 25, 1886. 
[Plates 2-5.] 
Contents. 
PAGE. 
Chapter I.—Muscles of the Cloaca . 9 
Muscles of the Cloaca of the Crocodilia .. 10 
Cloacal and copulatory muscles of Chelonia . 10 
„ „ Birds. 11 
,, „ Sauria . 12 
„ „ - Hatteria .. ... 12 
„ „ Mammalia. 12 
Chapter II.—The nerve-supply of the Cloacal region in Crocodiles. ... 14 
Chapter III.—The modifications of the Cloaca .. 15 
Crocodilia.. .. 16 
Sauria ... 18 
Ophidia . 18 
Hatteria . 19 
Aves. 20 
Chelonia. 21 
Anal pouches. 22 
Peritoneal canals. 23 
Monotremata .. 26 
Marsupialia ... 26 
Placentalia . 27 
Summary of Chapter III. ... ... 28 
Chapter IV.—On the presence of Mullerian ducts in the males, and of Wolffian 
ducts in the females of young Crocodilia . 30 
Chapter V.—General conclusions . 30-32 
A rich material of Crocodiles and Alligators Las enabled me to clear up several 
points in the structure of their sexual apparatus, which have hitherto escaped 
notice, probably owing to the scarcity of suitable specimens. This latter difficulty 
has been removed in my case by the liberality of the University of Cambridge and 
of the lioyal Society, which has enabled me, in conjunction with Dr. Gaskell, to 
MDCCCLXXXVII. — B. 27 4 87 
