510 ANNELIDA. 



the glandular layer. Sexual maturity seems to be more or less 

 continuous. Oviducal pores always on segment 14, and ovaries in 

 segment 13. 



Fam. 1. Moniligastridae. Large or small earthworms with paired setae, 

 8 per segment; clitellum 10-13, inconspicuous, one cell thick. One pair of male 

 pores in Moniligaster, between 10 and 11, testes in 10 ; two pairs in Desmo- 

 gaster, on 11 and 12, testes in 10 and 11. Spermiducal gland showing the same 

 structure as in the Lumbriculidae, with sometimes a protrusible penis. Ovaries 

 in 13 in Desmogaster and some species of Moniligaster, in 11 in other species of 

 M. Egg-sacs large ; eggs smallish, larger than those of other Earthworms, 

 smaller than those of aquatic forms. India, Ceylon, Sumatra, Borneo, Burmah, 

 Bahamas. Moniligaster Per. ; Desmogaster Rosa. This family of earthworms 

 is placed by some zoologists amongst the Limicolac, because of the position and 

 structure of the clitellum, the length of the vas deferens, and the position 

 of the ovaries in some species. Terricolous. 



Fam. 2. Perichaetidae. With numerous setae in each segment arranged in a 

 continuous circle, or with dorsal and ventral gaps ; male pore nearly always on 

 18. Gizzard always present; intestine frequently with two (sometimes more) 

 caeca and a rudimentary typhlosole. Nephridia diffused or paired. Spermiducal 

 glands generally lobate ; penial setae present or absent ; spermathecae with one 

 or two diverticula. 



Perichaeta Sehmarda, very active, setae usually in a continuous row, nephridia 

 diffuse, mainly tropical Oriental, also in Australia, Europe and America ; 

 Megascolex Templeton, setae interrupted dorsally and ventrally, nephridia diffuse 

 and paired, Australian and Oriental; Plcionogaster Michaels., Philippines; 

 Perionyx Perr. , tropics Old World ; D/porochaeta Bedd. , N. Z. and Australia. 



Fam. 3. Cryptodrilidae. Terrestrial, sometimes aquatic, with 8 setae per 

 segment. Clitellum variable in extent, occupying some or all of segments 

 12 to 23, usually complete anteriorly. Spermathecae one to five pairs, placed 

 anteriorly, nearly always with one or two diverticula. Male pores on segment 

 17 or 18, opening independently of or into the distal non-glandular part of the 

 Spermiducal gland, which is either tubular or lobate. Penial setae generally 

 present. Nephridia paired or diffuse. The large number of new forms which 

 have been described make it a difficult matter to separate the genera. In most 

 parts of the world, but mainly tropical, specially Australian. This family inter- 

 digitates with the Acanthodrilidae and with the Perichaetidae, from which the 

 only difference is the character of 8 setae per segment, which, indeed, is shared 

 by the anterior (though not the posterior part of the body) of Megascolex. 

 Microscolex Rosa, mainly S. America ; Pontodrilus Perr. ; Typhaeus Bedd. ; 

 Dichogaster Bedd. ; Deodrilus Bedd. ; Millsonia Bedd. ; Fletchcrodrilus Michaels; 

 Trincphrus Bedd., 3 pairs of nephridia in each segment; Digastcr Perr.; 

 Megascolides McCoy; M. australis Spencer, the giant earthworm of Gippsland, 

 1 '23 m. ; Cryptodrilus Fletcher ; the last five genera are mainly confined to 

 Australia; Microdrilus Bedd., Java, very active; Gordiodrilus Bedd., mainly 

 trop. Africa ; Ocncrodrilus Eisen, America and Africa ; Nannodrilus Bedd., 

 West Africa, aquatic. 



Fam. 4. Acanthodrilidae. Large or small, usually terrestrial, rarely aquatic. 

 Setae 8, 12, or numerous. Male pore on 18 ; pores of Spermiducal glands, 

 which are tubular structures generally with penial setae, on 17 and 19. 



