1 '2 
DK. H. GADOW OX THE CLOACA AXD OX THE 
In those Carinatse which, like the Anatidce, possess a copulatory organ, the latter is 
placed slightly asymmetrically on the left side of the ventri-lateral cloacal wall. In 
connexion with its basal portion are several muscular bundles, which somehow seem to 
be able to protrude and to retract the penis. They are merely branches from the 
inner portion of the voluntary sphincter ani, which itself in its ventral half is more 
developed towards the left side. It seems probable that through the action of the 
inner portion of the M. sphincter the vestibular walls can be everted, and that with 
them the penis is protruded. 
In the Ratitce the strongly-developed copulatory organ necessitates the presence of 
special copulatory muscles. There is in Rhea on each side a M. protractor penis, 
which in a similar way as in Anas is developed from an inner layer of the sphincter, 
but it goes as a rather independent muscle to the lateral portion of the basis penis. 
In Struthio it receives a slip from the M. transverso-analis, which descends from the 
pelvic bones. A pair of retraotores penis arises from the pelvis, and is attached to 
the ventral aspect of the middle portion of the organ. 
The copulatory muscles of the Carinatse are consequently derived from the M. 
sphincter ani solely, whilst in the Ratitse they are partly also differentiations of 
muscles, which are still attached to the pelvis, and are therefore skeleto-genital. 
Saurii. —The numerous anal and copulatory muscles of the Lacertilia have been 
described and figured in the ‘ Morphologisches Jahrbuch,’ vol. 7. The striped retractor 
muscles of the two penes cannot be compared to any of the other Sauropida, although 
they are likewise differentiations either of the ventral caudal muscles or of the M. 
sphincter. The latter is almost independent, arising, however, from some of the first 
transverse processes of the tail vertebrae. Hatteria possesses a M. perinei s. trans¬ 
verso-analis like the Lizards ; also a M. transversus medianus almost exactly like that 
described in the Crocodilia; its most superficial fibres are transformed into a distinct 
outermost sphincter, which, according to the shape of the anal opening, lies trans¬ 
versely and not longitudinally as in the Crocodilia. 
From the outside of the M. transversus medianus, and covered by the M. sphincter, 
starts on each side a broad but thin muscle, which runs back and attaches itself 
aponeurotically on the skin and on the fascia of the ischio-caudalis, behind the anus. 
It resembles a very similar pair of muscles of the Lizards. 
The odoriferous glands receive a coating of striped muscular fibi'es from the M. 
transversus medianus. 
The anal and copulatory muscles of the Mammalia show the greatest differentiation. 
In the Monotremata a broad, striated muscle arises from the ischium and attaches 
itself with a small portion to the root of the crura penis, sending at the same time 
fibres along the dorsum of that organ; it is a M. ischio-cavernosus; its greater 
portion, however, runs along the ventral and lateral walls of the cloaca, attaches 
itself to them, and extends as far as the sphincter ani, with which its fibres partly 
blend. Through the action of this muscle undoubtedly the cloaca can be considerably 
