92 Mr. F. E. Beddard on Earthworms firom 



the gland. A simple tubular prostate is characteristic of the 

 genera Euchilus^ Pontodrilus^ and Typhoeus, where it is either 

 a straight uniform tube {Eudrilus) or curved. AcantJiodrilus 

 for the most part agrees with the last-named genera in the 

 form of the prostate glands, but differs in so far that there are 

 two pairs instead of only one. In some genera [Lumhricus, 

 Microc]i(xta) there are no prostate glands at all. Perichmta 

 ceyhnica therefore combines the characters of Perichoita and 

 Acanthodrilus \ it agrees with the former genus in the distri- 

 bution of its setaj, while the generative organs approximate in 

 many points to those of Acanthodrilus. 



In Acanthodrilus^ as already stated, there are two pairs of 

 prostate glands, to each of which corresponds a bundle of 

 penial setai ; the apertures of these glands are, in the majority 

 of species, upon the 16tli and 18th segment; there is usually 

 a segment interposed between the two pairs of orifices. In 

 one species, however, if I do not misinterpret M. Perrier's 

 statements, there is a slight difference. In this species {^Acan- 

 thodrilus verticiUatus) the two pairs of orifices are more 

 closely approximated, being situated upon the 17th and 18th 

 segments. Perichceta ceyhnica forms a third term in the 

 series ; there are four male generative apertures, but these are 

 all upon the same segment (thel8tli), one pair behind the 

 other *. Finally we have, as in the vast majority of earth- 

 worms, a single pair of male generative apertures with or 

 without prostate glands. It is interesting also to notice that 

 the prostate glands of P. ceyhnica combine characters that 

 are found in different genera, but here united in the same 

 species ; one pair of prostate glands are typically " Perichse- 

 tous ; " the anterior pair are like those of Pontodrilus and 

 other genera. 



There is a single pair of copulatory pouches present which, 

 as already observed, open to the exterior on tlie boundary- 

 line between the 8th and 9th segments : the copulatory 

 pouches are large in proportion to the size of the animal ; 

 each is furnished with a simple diverticulum, as in P. post- 



* Perhaps the genus Eudrilus resembles Perich(eta cei/Ionica in these 

 respects. M. Perrier's description of the male geueratiye organs in that 

 genus are unfortunately not very complete, owing to the inferior state of 

 preservation of the specimens at his disposal. In the description of the 

 genus Eudrilus (Nouv. Arch, de Mus. t. viii. p. 74) he speaks of two 

 different glandular (?) structures uniting together with the vas deferens 

 to open to the exterior; the first of these is an elongated organ, which 

 is compared to the prostate of other earthworms ; the second is a Y- 

 sbaped tuhe which opens into the dilated distal extremity of the vaa 

 deferens separately fi-om the former. These structures are stated to occur 

 in jEJ. Lacazii, E. j^.eregrinus, and E. dccijnens. 



