1G8 THE VOYAGE OF H.M.S. CHALLENGER. 



(fig. 8, I) and the bulbo-cavernosi (fig. 8, h) are identical in every respect, whilst the 

 ischio-cavernosi (fig. 8,f) differ in having no pelvic attachment. 



The levatores penis (fig. 8, i, and fig. 9, e) lie upon the under surface of the organ. 

 Each muscle springs from the corresponding crus and inclines towards the mesial plane, 

 where it joins its fellow of the opposite side to form a narrow tendon. This is continued 

 onwards to be inserted into the base of the glans. 



Anal glands (fig. 11, b, b 2 , 6 3 ). — These glands may be conveniently noticed here. 

 They are six in number. Three are situated upon either side of the common opening 

 into which they open by long independent ducts. Each gland has a muscular capsule, 

 and consists of a single large chamber which, in the specimen examined, was filled with a 

 brown curdy secretion. The largest of the series was about the size of a marble, whilst 

 the smallest was as large as a haricot bean. 



In the Vulpine phalanger the same number of anal glands is present, but they are 

 much smaller in size. In the Thylacine they are absent. 



Sphincter cloacce. — This muscle presents the same connections in both Tliylacinus and 

 CuscUs. It forms a complete sheath for the anus and the numerous glands, and parts in 

 connection with the root of the penis. The glands, &c, are packed within it, in the midst 

 of soft fat. Above the common opening it is present in the form of a strong narrow 

 muscular bundle. As this is traced forwards, it is observed to expand, so that on the 

 inferior aspect of the opening it constitutes an exceedingly thin muscular web — so thin, 

 indeed, that the structures it encloses shine througdL it. In front, this thin sheet of 

 fibres has a distinct attachment on either side to the crus of the penis ; behind its fibres 

 are inserted into the skin surrounding the mouth of the common opening. It has no 

 attachment to bone. 



Marsupium of the Female Thylacine. 



The marsupium of the female Thylacine which I examined, is figured in Plate IV. 

 (fig. 3). It was evidently a very young specimen. This was manifest not only by its small 

 size but also by the immature condition of its bones. I am inclined to believe that it 

 had never borne young. 



The marsupium was oval in form and exceedingly shallow. Its long axis, which was 

 directed from before backwards, measured two inches, whilst its transverse diameter was 

 one and a half inches. In front and behind there was little or no demarcation between 

 the pouch and the surrounding skin of the abdomen. Laterally, however, it was well 

 mapped out by prominent overhanging folds of integument. The skin forming these 

 folds and the floor of the marsupium, was of a very delicate texture and slightly wrinkled. 

 With the exception of some sparse white downy hair it was quite bare. At the limits of 

 the pouch this downy hair was suddenly replaced by the ordinary hairy coat of the animal. 



