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 Desmogaster), 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 : — 



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



(2) „ barwelli, F. E. B., Manila. 



(3) „ liouteni, HoRST, Sumatra. 



(4) „ japonicus, MiCH., Japan. 



(5) „ bahamensis, F. E. B., Bahamas. 



(6) „ indicus, Benham, India. 



(7) „ beddardii, EoSA, Burmah. 



(8) „ grandis. Bourne, India. 



(9) „ uniquus. Bourne, India. 



(10) „ sapphirinaoides. Bourne, India. 



(11) „ robustus, BOuRNE, India. 



(12) „ papillatus, Bouene, India. 



(13) „ ruber. Bourne, India. 



(14) „ minutus, Bourne, India. 



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

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



Moniligaatef 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 uniquus 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. 



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



