ON THE BRITISH ANNELIDA. 261 



pletely formed worms, or surrounded by a dense and tough case which gives 

 them the character of pupae. Whether they are produced in the perfect or 

 in the pupal form, depends on the nature of the soil which the worms inhabit. 

 In alight and loose soil the young quit the parent prepared to act for them- 

 selves ; but in a tough clayey soil they continue the pupal form for some 

 time, so as to arrive at a still higher degree of development, before commen- 

 cing to maintain an independent existence*." It is thus seen that Mr.Rymer 

 Jones has copied from Sir E. Home and M- Duges, and Dr. Carpenter has 

 copied from Mr. Rymer Jones, neither writer having attempted to deter- 

 mine the truth or falsehood of the statements which he was transmitting to 

 another generation. Thus ever has error been propagated. 



All that is true in the original description of Duges with regard to the re- 

 productive organs of the Earth-worm, amounts to no more than what the most 

 cursory dissector may readily verify, viz. that there exists near the base of the 

 oesophagus a mass of glandular bodies, which are described as ovaria, and 

 which, when the contents are mature, are said to burst. It is no severity of 

 criticism to remark that this latter idea indicates a very rude state of physio- 

 logical knowledge on the part of those by whom it is entertained. The de- 

 hiscence of large vital organs, like the ovaria, is an occurrence which has 

 never been credibly authenticated in the animal kingdom. In the vegetable 

 kingdom it may be a normal event. The researches of Quatrefages have 

 thrown no additional light whatever on the anatomy of this system, having 

 mistaken the true utero-ovaria for lateral secreting pouches. Amid so little 

 that was clear, and so much that was confused, it became obvious therefore 

 that nothing less than independent and patient dissections would solve the 

 enigma as to the mechanism of reproduction in this worm. The author 

 trusts that he will be able to show that he has satisfactorily accomplished 

 this object. 



The first part of the reproductive system observed on opening the body 

 along the dorsal median line, is the glandular white mass which embraces 

 the oesophagus (as shown in Plate IX. fig. 66 a, a, in a pregnant individual). 

 The component lobuli of this mass vary in size and number, according to 

 the age of the specimen under inspection. They are tied down to the in- 

 tersegmental partitions, and communicate (fig. 67 a, in an individual not 

 pregnant) with minute ducts which run longitudinally on either side of the 

 median line, from one end of the body to the other (fig. 66 b, b). When 

 compressed they discharge a milky fluid, which is their proper secretion. It 

 is true seminal fluid ; it is not emitted directly externally, but into the longitu- 

 dinal ducts (b, b, fig. 66 and b, b, fig. 67) through the excretory channels (a, a), 

 which are common to the whole utero-ovarian system. From these longi- 

 tudinal conduits the fertilizing fluid passes laterally along still minuter ducts 

 (b, b, b, fig. 67, and a, fig. 68), which open directly into the utero-ovarian 

 sacculus. In fig. 68 spermatic animalcules are represented in progress of 

 passage from the longitudinal ducts into the lateral duct (a), which conveys 

 them immediately into contact with the ova (6). This fact of the actual 

 presence of sperm-cells in this duct of the female system dispels every obscu- 

 rity with respect to the mechanism of self-impregnation, probably in all An- 

 nelida. In fig. 67 is represented the copulative pouches, so called because no 

 other probable use can be assigned to them (c, c). They are unquestionably 

 an integral part of the generative apparatus, though their functions may only 

 be mechanical. In the Earth-worm they are concealed by the testicular 

 masses. These latter organs in fig. 67 are removed in order to display the 

 copulative pouches (c, c, c), which amount to four or six in number on either 

 * See last edition of Dr. Carpenter's Principles of Comparative Physiology, pp. 954 and 955. 



