Alien Oligochxts in England. By Rev. H. Friend. 265 



behind the ovary, while in I) id cog aster there are usually three 

 pairs of these organs present. 



Since Beddard founded the genus Dichogaster it has been 

 greatly extended, Michaelsen, so long ago as 1900, enumerating 

 no fewer than ()7 species. His definition of the genus so extended 

 is as follows : — 



" Setffi in pairs on the ventral side. Prostate pores 1-3 pairs 

 on 17-19 segments. Spermathecfe 1 or 2 pairs opening in 7/8, 

 8/9. Two gizzards anterior to the male organs ; sometimes only 

 2 pairs, but usually 3 pairs of calciferous glands beliind the 

 segment which carries the ovary, usually in segments 15-17, in 

 rare cases beginning one segment earlier. So far as known two 

 pairs of testes and funnels." A good deal is to be desired in this 

 definition, and doubtless as our knowledge of this large and complex 

 group of worms increases things will assume a more satisfactory 

 form. 



II. — Distribution. 



The first species of Dicliogaster to be described was received 

 by Beddard from Figi {D. damonis). In 1891 Michaelsen described 

 a second species {D. mimus) from Accra, West Africa {9); and 

 a third species the same year {8) from the same country. In 

 1900 {10) he summarized the known distribution in the following 

 words: — "Tropical Africa (from Abyssinia to Mozambique on the 

 one side, and from Portuguese West Africa to the Congo on the 

 other), Antilles, America (from California to Guatemala and 

 Dutch Guayana), Polynesia, Hawaii, Isle of Sunda, South Asia. 

 Certainly endemic in Tropical Africa, and probably so for the 

 Antilles and Central America. Some species have been intro- 

 duced into various lands, including Upper Guinea, Madagascar, 

 the Antilles, California, Mexico, Venezuela, Paraguay, Argentina, 

 Germany and the East Indies." We have no means of knowing 

 the original home of the species now under review. 



III. — Description of Dicliogaster lag eni for mis sp. n. 



As stated in my former paper, two years ago, while on a visit 

 to Oxford I found in the Lily House at the Botanical Garden a 

 species of worm which I had not previously seen. It was very 

 tender, and perished before I could reach home. In June, 1915, 

 I was able to pay another visit to the Garden, when I found 

 Kerria rubra, Dichogaster lageniformis, and another worm which 

 still awaits description. It is upon longitudinal sections of these 

 worms that our present study is based. 



External Chareicters. — Dichogaster lageniformis is a small 

 slender and delicate worm, extending when in motion to about 



