THE ANATOMY. SPERMATHECAE 133 



since the spermatheca of that worm is morphologically a different thing from the 

 spermatheca of those types that have just been mentioned. 



There are some facts which tend to prove that the spermathecae are, like the 

 spermiducal glands (see above), derived from copulatory glands ; the facts, however, 

 are not so conclusive in this case as they are (in my opinion) in the other case. 

 It must be noted, in the first place, that copulatory glands with modified setae occur 

 in the neighbourhood of the spermathecae. They have just been mentioned. There are 

 therefore no reasons against such an origin as there might perhaps be were the glands 

 in question never present in the anterior region of the body, but always confined to 

 the neighbourhood of the male-pores. Whether the glands in the anterior region 

 of the body are exactly similar to those in the posterior region is not certain ; some 

 facts tend to show that they are. In Ehynchelmis, for example (VE.TDOVSKY 5), 

 the albumen-gland is lined by two layers of cells, and recalls in this particular the 

 spermiducal gland of the same species. The great similarity, too, between the setae 

 which accompany the glands in Acanthodrilus ungulatus to the penial setae of the 

 same species are facts which point in the same direction. 



The spermathecae are lined with a single layer of epidermis, and appear at first 

 to differ very greatly from the glandular bodies with which it is sought to compare 

 them. It must be borne in mind, however, that in certain Oligochaeta in many 

 Enchytraeidae a smaller or greater part of the spermatheca is covered with a glandular 

 layer, which seems to me to be strictly comparable to the glandular investment of 

 the spermiducal gland. Even in the higher Oligochaeta this condition is not 

 altogether unknown. Perichaeta houlleti is characterized by the fact that there is 

 appended to the spermathecae a pear-shaped body, described by PERBIEE as 

 a diverticulum, but shown by myself to be simply a mass of pear-shaped glandular 

 cells. The relations of this to the spermatheca are very similar to those of the 

 ' Cementdriise ' to the 'atrium' in Tubifex*. 



There are two other points in which the spermathecae seem to show a resemblance 

 to the spermiducal glands, and therefore to the copulatory glands, from which it is 

 assumed that the latter have arisen by a slight modification. In Psammoi'ycteti 

 the long spermatheca has a diverticulum which lodges a penial seta. Its relations 

 to the spermatheca are exactly similar to those which exist between the copulatory 

 glands and their modified setae. The other resemblance is rather with the spermiducal 

 glands, but it obviously amounts to much the same. In Moniligaster bahamensis 

 (BEDDARD 57) and in Moniliyaster indicus (BENHAM 16) the spermathecae do 

 not, as is ordinarily the case, open directly on to the exterior of the body ; their 



1 Cf. also the cap of glandular cells figured by me (28) in the spermatheca of Diachaeta littoralis. 



