MAY, 1921. AMERICAN MARSUPIAL, CENOLESTES OSGOOD. 65 



the dorsal surface of the glans by a vertical slit. In life it would doubtless 

 function almost as efficiently as a closed tube. The surface of the glans 

 is slightly rugose in its proximal two-thirds and distally it is covered 

 with small circular papillae. The total length of the cleft part of the 

 glans is approximately 1 2 mm. The penis when retracted lies in a pouch 

 formed by the expanded distal part of the urethra and opening into the 

 cloaca (See PL IX, Fig. 3). 



The retractor muscles of the penis are attached one on each side 

 near the anterior end of the penis pouch. They originate from the 

 narrow tendons of the infracoccygeus on the ventral surface of the 

 fifth lumbar vertebra and run for a short distance caudad above the 

 colon and then turn slightly ventrad, inclosing the colon and continuing 

 caudad along its latero-ventrad surf ace, and pass dorsad of the Cowper's 

 glands to their insertion on the sides of the penis pouch. 



The cloaca, the penis pouch, and at least certain of the Cowper's 

 glands are enveloped in a thin layer of muscle, the sphincter cloacae and 

 its accessory folds. About the cloaca it is thicker and the fibers have a 

 circular course, but more anteriorly it becomes thinner and follows the 

 interstices between the organs where it is lost in the connective tissue. 

 Anteriorly it is attached by the flat tendons to the ventral surface of the 

 pubic symphysis. These, in crossing the ventral surface of the urethra, 

 have partial attachment near the base of the corpus cavernosum. 



The testes are of relatively large size, broadly elliptical in shape and 

 slightly flattened on one side where the two are closely appressed in the 

 scrotum. A single one in a preserved specimen measures 6.5 x 4.5 mm. 

 The testis is clasped by the epididymis in the usual manner and loosely 

 attached. The globus major is somewhat thickened and has consider- 

 able convexity. It is slightly larger than the globus minor which lies 

 folded upon itself and in its course toward the exit of the vas deferens 

 has several convolutions which lie against the testis in the inferior 

 curvature of the epididymis. Part of this is evidently the vas deferens 

 itself and its position here is evidently somewhat peculiar since the 

 arrangement in Didelphis and Macropus is not quite the same. 



The most noteworthy features of the male generative organs of 

 C&nolestes are the extraordinary size of the prostate and Cowper's 

 glands, the very deeply cleft glans penis, and the absence or great re- 

 duction of the levator penis muscle. It is difficult to see indications of 

 relationship in any of these. The bifid glans penis occurs in both 

 polyprotodonts and diprotodonts. It is most pronounced in polyproto- 

 donts and, according to Owen (Anat. Vert., Ill, p. 648), is associated 

 with the presence of a levator penis muscle. But in C&nolestes there is 

 the unusual condition of a deeply bifid glans penis and a rudimentary 



