ON THE BRITISH ANNELIDA. 255 



posteriorly to it on the same side. In minute structure this body is precisely 

 the same as the bodies of the testicular series ; like them it is filled with sperm- 

 fluid ; the interior is a cavity. The secreting glandular structure is disposed 

 around the circumference ; the secreted product is thrown into the enclosed 

 hollow. This description applies also in every particular to the other testi- 

 cular bodies, which are like the former, hollow orbicular glands. The large 

 longitudinal duct which serves as a common channel of communication be- 

 tween all the testes, emerges out of the gland (Ji) under the character of a 

 duct of greatly reduced size (i). This small tubular thread, traced with 

 minute care, may be followed into the median glandule {j) to which the 

 penis (k) is appended. In the median line also, and some little distance pos- 

 teriorly to the body just described, may be remarked a pear-shaped sac- 

 culus (/) from the unattached fundus of which a caecal coiled tubule (m) is 

 prolonged. Between this saccular and the other parts of the reproductive 

 system, no communication of any description can be discovered. It seems 

 simply destined to receive the intromittent organ developed in connexion with 

 the gland situated in advance of it on the median line. 



It may be inferred from the character of the whole system of the testicular 

 bodies, that the penis is not an ejaculatory organ ; it seems subservient only 

 to the purposes of sexual stimulation. By all anatomists, from the date of 

 the first description of M. Duges, this sacculus has been regarded as a uterus, 

 and as, in fact, constituting the whole of the female element of the generative 

 system. The convoluted caecal tubule pendent from the fundus of this sac- 

 culus, including some undiscoverable gland structures on either side of it, 

 are commonly indicated as the ovaria. Such anatomists, whilst entertaining 

 opinions so remote from the truth, and withal so little probable on physiolo- 

 gical grounds, never could have seen these parts. An ovarian system so 

 utterly disproportionate to the testicular, if it were true, would find no prece- 

 dent or parallel in the whole series of invertebrate animals. 



In all hermaphrodite animals the female elements of the generative organs 

 are invariably superior in size, more elaborately organized, and more important 

 as constituent parts of the whole organism, than the male : wherefore should 

 the converse of this rule obtain in the Annelida ? A cursory glance at the or- 

 ganic necessities of the animal system should have sufficed to convince the 

 physiologist that such a simply organized sac, so uncomplicated in structure, 

 so unprovided with stromatous tissue for the production and development of 

 ova, could not have proved adequate to those profound functions involving in 

 intimate sympathy every other of the organism which are concerned in the 

 continuation of the species. It was the necessity, thus perceived on theo- 

 retical grounds, for some series of organs which would reasonably answer to 

 the general characters of a female system, which first led the author to the 

 discovery of that which now remains to be explained. 



In the Leech, the female system consists of a greater number of separate 

 parts than the male, amounting to fifteen or seventeen on either side, while the 

 testicular bodies are only nine. This system is composed of a linear succes- 

 sion of a bag-pipe shape, membranous sacculi (fig. 65 b, b, b, &c.), contracting 

 at both ends into two separate ducts. One of these ducts {I, I, I, &c.) termi- 

 nates an orifice communicating externally. It is through this orifice that the 

 ova and young escape from the ovarian utricle into the external medium. In 

 the Leech, the ova in this duct, in every case yet examined, present an ob- 

 viously greater degree of development than those which are found in the duct 

 (.9i9^ B) which communicates with the neighbouring testis. At certain sea- 

 sons of the year, in the Earth-worm, this duct, which may be called the 

 inferior duct of the ovario<uteriue organ, is crowded with living young, emer- 



