PLATANISTA. 475 



surrounded by the spongy tissue just mentioned, which is of a highly erectile 

 character, the lobes consisting exclusively of this tissue except when the corpora 

 cavernosa are prolonged into them. 



I have stated that the cavernous bodies may either pass into the lobes of the 

 glans or stop short of them, an observation which I am enabled to make, having 

 examined two organs in which this variation is shown. On the right side of one, 

 the anterior crus passes for a full inch into the lobe directed forwards and outwards, 

 while the other of the opposite side is projected into its lobe for only 0-50 inch ; but 

 0-36 inch anterior to its rounded termination there is an isolated piece of brown 

 tissue of the same nature as its spongy substance, 0-36 inch in length and invested 

 by a fibrous capsule. It is placed transversely and connected to the end of the 

 crus by a line of fibrous tissue. In the other penis the corpus cavernosum is found 

 extending 1 inch iato the left lobe, but no trace of it can be detected on the right 

 side iu which its blunt end is observed at the base of the glans. 



In the filiform process, the spongy body soon unites with the other erectile 

 tissue which surrounds it, and the resultant structure is prolonged to the extremity 

 of the process, becoming finer and finer and less dense as it nears the point. 



The preputial sheath is 7 inches long and the circular fibres which form it 

 appear to be derived from the panniculus carnosus muscle and extend backwards to 

 behind the first bend. 



The erector penis invests all the sides of the crus of the cavernous body except 

 the inner face and the last half inch internally of its superior margin, which gives 

 attachment to a bundle from the ejaciilator seminis. It consists of fibres which 

 arch downwards from the upper to the lower margin, where they terminate in a very 

 strong glisteniug fascia adherent to the under surface of the crus. 



Ejaculator seminis. — This muscle is very thick and encloses the spongy 

 substance. It arises from the strong fascia attached to the inner wall of the fibrous 

 covering of the corpora cavernosa, and the fibres stretch from before backwards and 

 inwards, outwards and upwards to be fastened to the fascia in connection with the 

 upper surface of the crura common to the two muscles. A few are also attached 

 to the strong rectal fascia. Anterior fibres are du'ected downwards and backwai'ds 

 to meet the fellows of the opposite side in a strong fascia behind the bulb, and have 

 the retractor muscle lying below them. 



A strong muscle {levator ani) arises from the posterior extremity of the out- 

 wardly prolonged lamella of the fibrous investment of the crura, and expands 

 towards the middle Mne over the hinder end of the ejaculator seminis, to become 

 invested along the rectum by a wide surface and to mix with the sphincter ani. 



Retractor muscles. — These are two long cord-hke structures fixed posteriorly to 

 the strong fascia covering the anterior surface of the ejaculator, and lying alongside 

 of the rectum. Passing out between the two ejaculators they, of course, press against 

 the bulb and rest on the hne of union of these two muscles and the membranous 

 portion of the urethra. The muscles are in close contact till they appear beyond 

 the ejaculator muscles where they diverge to reach their respective sides of the penis. 



