198 OLIGOCHAETA 



epithelium, surrounded by a layer of circular muscles, which is itself surrounded 

 by a layer of large pyriform cells, whose prolongations penetrate the muscular and 

 epithelial layers to communicate with the lumen of the organ ; near to the summit 

 of this glandular part of the organ opens the sperm-duct. (5) The ovaries are 

 generally in the segment which follows that containing the testes ; the oviducts 

 lie opposite to them, and, therefore, open on the exterior between segments xi/xii ; 

 a most characteristic feature of the genus (and of the closely allied Desmogaater), viz. 

 the large egg-sacs has been already spoken of. (6) The spermathecae are a single 

 pair only ; they usually lie in the eighth segment ; each consists (except in 

 M. japonicus) of a small globular pouch communicating with the exterior by 

 an extraordinarily long duct, which has well-marked muscular walls. It is not 

 an easy task to discriminate the various species of Moniligaster which have been 

 described ; altogether the following thirteen species have received names : 



(1) Moniligaster deshayesi, E. P., Ceylon. 



(2) barwelli, F. E. B, Manila. 



(3) houteni, HORST, Sumatra. 



(4) japonicus, MICH., Japan. 



(5) ,, bahamensis, F. E. B., Bahamas. 



(6) indicus, BENHAM, India. 



(7) beddardii, ROSA, Burmah. 



(8) grandis, BOUBNE, India. 



(9) uniquus, BOURNE, India. 



(10) sapphirinaoides, BOURNE, India, 



(n) robustus, BOURNE, India. 



(12) papillatus, BOURNE, India. 



(13) ruber, BOURNE, India. 



(14) minutus, BOURNE, India. 



Seven of the species in the above list are too imperfectly known to admit of 

 thoir being defined in a way sufficient to discriminate them from those that are known. 



Moniligaster grandis appears to possess five gizzards (in segments xvii-xxi) ; the septum between 

 segments ix/x is missing ; but BENHAM throws some doubt upon this fact, and explains it by the 

 shifting of the septa, which does take place elsewhere. 



Moniligaster uniqinig has gizzards in xv-xix and is a small species. 



Moniligaster sapphirinaoides has gizzards in the same segments as M. grandis, but appears to be 

 a smaller form. 



Moniligaster robustus has the gizzards in an unusually anterior position, viz. in segments xi-xv. 



Moniliguster papillatus is chiefly defined by 'long tubular papillae in connection with the pores 



