1892.] FROM ALGERIA AND TUNISIA. 29 



rich, though at present but Httle known ; but the Sahara has proved 

 here, as it has in the case of other animals, to be a barrier preventing 

 the northward range of these forms. Only in Egypt are there any 

 genera found also in Tropical Africa ; the very remarkable genus 

 Siphonogaster occurs in Egypt and in the neighbourhood of Lagos, 

 W. Africa. But the banks of the Nile, or even the river itself (for 

 many species of Earthworms can withstand a prolonged immersion in 

 fresh water), have furnished, no doubt, the opportunity of migration. 



Mr. Alvan Millson, Colonial Secretary at Lagos, kindly collected 

 for me a number of Earthworms in Egypt ; all these species were 

 members of the genera Lumbricus and Allolobophora. 



Besides Leviusen's paper upon Siphonocjaster and Digitibranchus 

 (=Ahna) we do not possess, I believe, any further information upon 

 the Oligochseta of Egypt than that which has been given in the 

 preceding sentence. 



Dr. Anderson's collection contains examples of two recognizable 

 species, Allolobophora complanata and Microscolex modestus. Besides 

 these, tliere are two or three immature forms of the genus Allolo- 

 bophora which are not old enough for identification. 



Allolobophora complanata (Dugcs). 



Lumbricus eomplanatus, Daghs, Ann. Sci. Nat. t. viii. pp. 17,22. 



This species is a well-known South-European form, having been 

 met with in S. France, Italy, Portugal, and the Balearic Islands. 

 I now add Algeria to the list of localities whence it has been ob- 

 tained. The principal information fis to the structure of this species 

 is to be found in Dnges's memoir upon the Earthworm, in Rosa's 

 account of the Lumbricidae of Piedmont \ and in a paper by myself 

 devoted to this species ". Li neither of two specimens belonging to 

 Dr. Anderson which I dissected was there any trace of the peculiar 

 diverticula of the spermathecse which I described in the paper last 

 referred to. 



As neither Duges nor Rosa observed anything of the kind, it is 

 possible that the individual I described should be regarded as a 

 variety of the more typical form, the occurrence of which in Algeria 

 I here record. 



Microscolex algeriensis, n. sp. 



There is only a single specimen of this species, which I investi- 

 gated by means of longitudinal sections of the head end. The 

 structure of the posterior segments was examined by mounting 

 portions of the body in glycerine after having been cut open. 



It is a small worm, measuring only an inch or so in length and 

 composed of 80-90 segments. Being curled into a circle in the 

 preservation, I am not able to give exact measurements, which are, 

 however, not of very great importance. 



1 ' I Lumbricidi del Piemoiite,' Turin, 1885. 



^ " Observations on the Structure of Lumbricus eomplanatus, Dug.," Proc. 

 Eoy. See. Ediiib. xiii. p. 4.51. 



