262 ON EARTHWORMS FROM IJ^EW ZEALAND. [Kov. 15, 



The occui'rence of a prostate in Megascolides austraUs, similar 

 to that of a typical Acanthoclrihd, seems to indicate that the 

 confinement to a single segment is related to the cylindrical 

 form ; and it is admitted by Michaelsen that these " Cryptodriline " 

 worms, belonging to the subfamily Megascolecinte, are derived 

 from the subfamily Acanthodrilinte. And, on the other hand, 

 the peculiar foi-m of the gland in Notiodrihts auchlandicus 

 illustrates the relation between a looser structure and the 

 extension of the gland through several segments. But, although 

 this transition of form between the " tongue-shaped " and " cylin- 

 drical " tubular prostates seems to occur, yet the flattened form 

 appears a still later development ; it occurs, for example, in the 

 more modified genera, such as Pherethna. 



Miss Sweet has pointed out that in the " tubular " prostate 

 there is a lumen i-unning the whole length of the gland ; whereas 

 in the lobate foim of this organ there is, typically, no central 

 lumen, and when it exists it is not only very small, b\it it has no 

 epithelium. Unfortunately, the species examined by her do not 

 belong to the genera under dispute, with the exception of Mega- 

 scolides illaivarrce, in which the prostate is a " somewhat long and 

 flattened " oi-gan, and has a structure intermediate in some 

 respects between a truly " lobate " gland, such as exists in 

 Megascolex, and a " tubular " gland, such as occurs in Plutelhcs 

 and others; for the species referred by her to ^-Megascolides" 

 belong to the genus Flutelhos in Michaelsen's sense. 



If I have dwelt so much on the form of the prostate, it is 

 because it seems to me that Michaelsen has not laid sufiicient 

 stress upon this oi-gan in shufiling the members of the " Crypto- 

 driline series." It alone, I admit, will not serve for generic 

 distinction ; but it may possibly be iTsef ul in the formation of 

 subgenera. 



Dunedin, April 10, 1904. 



Bihliogra2}hy . 



'89. Beddard, F. E, " Oligochfetous Fauna of ISTew Zealand," 



in Proc. Zool. Soc. p. 377. 

 '90. " Classification and Distribution of Earthworms," in 



Proc. R. Phys. Soc. Edinb. x. p. 235. 

 '92, " On the Earthworms in the Vienna Museum," in 



Ann. Mag. Nat. Hist. (ser. 6) ix. p. 113. 

 '93. " Some new and little-known Oligochteta," in Proc. 



R. Phys. Soc. Edinb. xii. p. 33. 



'95. ' Monograph of the 01igocha3ta.' Oxford. 



'90. Benham, "W. B. "An Attempt to Classify Earthworms," 



in Quart. Journ. Micr. Sci. xxxi. p. 319. 

 '00 (a). " On Acanthodrilus uliginosus," in Trans. N.Z. 



Inst, xxxiii. p. 125. 

 00 {b). " On some Earthworms from the Islands around 



New Zealand," in loc. cit. p. 140. 



