liKlTISH ANNELIDS. 237 



embryo)iu\ those useful to the organism in its early stages ; (ii.) the 

 vestigia/, those useful to its ancestors, but now in process of abortion 

 through the operation of the law of economy of nutrition ; and (iii.) 

 the indifferent ancestral structures, structures originating in the vari- 

 ation which we call * spontaneous ' of its ancestors ; which, being 

 neither directly useful nor extravagantly wasteful of tissue — and there- 

 fore likely to become aborted — nor otherwise harmful, are inherited 

 unaltered. The indifferent class similarly includes all structures 

 originating in the free play of that ' spontaneous variation ' which 

 Mr. Wallace has shown to be so widely varied in its results, which 

 are neither directly useful nor harmful. Darwin showed that struc- 

 tures which I should refer to one or other of these classes, being 

 practically beyond the scope of natural selection, will be extremely 

 variable. Coming to Mr. French's immediate subject, I would 

 remark that he has confined his attention to the two species of 

 Dipsacus that happen to be British, whereas there are seventeen or 

 eighteen species of the genus, five or six of which occur on the con- 

 tinent of Europe ; and that D. sylvestris and D. pilosus belong to 

 different sections of the genus, the Eudipsaci and the Trichocephaia, 

 the latter approximating to the genus Cephalaria. I should be 

 interested to know whether Mr. French has ever observed the two 

 British species, or others, growing so as to compete with one another." ' 



— G. S. BOULGER.] 



BRITISH ANNELIDS. 



WITH ESPECIAL REFERENCE TO THE EARTHWORMS OF ESSEX. 



By REV. HILDERIC FRIEND, F.L.S. 

 {Continued from page tgd.) 



/^NLY a few words are necessary in order to present a bird's eye 

 ^^^ view of the different genera of British earthworms. The indi- 

 genous species belong entirely to one group, which has been, at the 

 most, divided into four sections, and as one of these divisions is not 

 at present retained (though it may at any time be revived), we have 

 practically only three distint genera to examine. These are Lum- 

 hricus, Allololwphora, and Allurus. The lapsed name is Dendro- 

 bcena, but we will not include it in our present study. Lumbricus 

 is distinguished from AUolobophora chiefly by the shape of the lip or 

 prostomium. In Lumbricus the foremost portion of the body and 

 the first ring form a perfect mortise and tenon, whereas in AUolobo- 

 phora the lip cuts but partially into the first ring. The first ring, 

 which bears no setae, is usually known as the peristomium. While 



I This I have not yet seen.— J. Fkenxh. 



