MALE GENITAL SYSTEM: INTERNAL ORGANS 377 



within the bulb of the penis to form a cms corporis spongiosi whose arms lie mesal and 

 ventral to those of the cms corporis cavernosi (Benham, 1901). 



The terminal cone 



It has already been remarked that Eschricht (1849) regarded the terminal cone of the 

 Cetacean penis as a true glans. Beauregard and Boulart (1882, p. 174) have a discussion 

 on the subject and arrive at the opposite conclusion. 



If we adopt the definition of a glans usually employed for man and other mammals— 

 namely the reflection of the corpus spongiosum at the termination of the corpus 

 cavernosum— then the terminal cone of the Cetacean penis cannot be called a glans. 

 Transverse sections across it (Fig. 4 A, B) show that the corpora cavernosa and 

 spongiosa continue together into the cone. The corpus cavernosum diminishes rapidly 

 towards the tip, retaining its reniform shape with its longest axis transversely directed. 

 The corpus spongiosum diminishes less rapidly and thus, within the cone, its cross- 

 section is considerably greater than that of the corpus cavernosum, in comparison with 

 which it becomes a wide structure with its long axis transversely directed (Fig. 4 B). 

 It is no longer embedded in a groove on the posterior aspect of the cavernous body, but 

 occupies, with its sheath, the greater part of the cross-section of the cone. The blood 

 sinuses in it increase in size and number. Its sheath becomes progressively thinner 

 towards the tip of the cone and at the extreme tip it finally disappears. Here (Fig. 4 A) 

 the corpus cavernosum finally tapers away altogether, and the whole substance of the 

 tip of the cone consists of spongy tissue derived from the corpus spongiosum. The whole 

 cone is highly vascular, especially the tip where the sinuses from the corpus spongiosum 

 reach the periphery. It is thus necessary to agree with Beauregard and Boulart, who 

 pointed out that there is no true reflection of the corpus spongiosum over the corpus 

 cavernosum and that the latter proceeds right to the tip of the cone. The terminal cone 

 is, therefore, not a glans in the true sense of the word. The same authors, describing 

 an adult cone 0-56 m. in length, found that 3-0 cm. from the extreme tip the cone "se 

 renfle legerement en une sorte de bourrelet circulaire", so that the posterior face of the 

 cone becomes obliquely truncated up to its extremity. An oblique concave surface is 

 thus constituted with the opening of the urethra in the centre. These authors were of 

 opinion that this concave surface corresponds to the glans and the circular fold (bour- 

 relet) to the corona. This homology, however, is difficult to establish. The part corre- 

 sponding to the glans, according to Beauregard and Boulart, is a concave surface, and 

 its underlying spongy tissue is the same as that which makes up the rest of the terminal 

 cone. It seems certain that the cone itself is not a true glans and it is proposed to employ 

 the term "terminal cone" when speaking of this part of the penis. 



The urethral canal, lined by a columnar epithelium several layers thick, occupies a 

 somewhat excentric position within the corpus spongiosum, lying slightly anteriorly 

 towards the corpus cavernosum (Fig. 4 E, F, G). The opening of the urethra at the tip 

 of the terminal cone occurs on the posterior face of the cone, and the anterior lip con- 

 siderably overhangs the posterior, as described by Beauregard and Boulart, causing the 



