[ 63 ] 



IV. On the Anatomy and Systematic Position of a Gigantic Earthworm (Microchaeta 

 rappi) from the Cajie Colony. By Frank E. Beddaed, M.A., F.R.S.E., F.Z.S., 

 Prosector to the Society. 



Received November 3rd, 1884, read November 4tb, 1884. 



[Plates XIV., XV.] 



Introductory Remarks. 



oOME forty years ago there was published in the ' Transactions ' of the Wiirtemberg 

 Academy of Sciences ' a brief account, accompanied by a plate, of a gigantic Earthworm, 

 a native of the Cape of Good Hope. The author of this paper, Dr. Rapp, contented 

 himself with describing the more obvious external and internal characters, and his 

 description will be considered in reference to the several points with which it deals in 

 the course of the present Memoir. Unfortunately at the time when Rapp published 

 his account of " Lumbricus niicrochceta," as he termed this Earthworm, the recorded 

 observations on the anatomy of the group were extremely few, and in consequence it 

 was impossible to compare its structure with other forms. It is not surprising, there- 

 fore, to find many structural details, which are now known to be extremely important 

 for classificatory purposes, omitted, and others too briefly described to be of much use, 

 in Rapp's paper ; it would, in fact, be quite impossible to decide upon the accurate 

 systematic position of Lumhricus microchceta from its perusal, although M. Perrier^ is 

 quite right in stating that it cannot at any rate belong to the genus Lumhricus as now 

 understood. 



Of late years more attention has been directed to this very interesting group of 

 animals, and we are now in possession of a very rational scheme of classification, which 

 is due to M. Perrier'*. This classification is based upon internal structure, though 

 taking in consideration also certain external characters ; the impossibility of deciding 

 upon the zoological rank and aifinities of an animal by external characters alone is 

 perhaps more strikingly emphasized in the Oligochaeta than in any other group in the 

 whole animal kingdom ; indeed it appears quite obvious that it should be so when we 

 consider that the differences of habit, physiological needs, and so forth cannot be great 

 between different species. 



Setting aside the previous systems of classification, which mainly depended upon the 



' Jahresheffc. d. Ver. f. vaterl. Naturk. in "Wiirtemberg, Jahrg. iv. (1848) p. 142. 



- Arch, de Zool. Exp. t. ix. p. 239, note. At the conclusion of his paper Rapp does suggest the formation 

 of a new genus Mkroclueta, which I adopt here, naming the species after Rapp, since he first described it. 



' NouveUes Arch. d. Museum, t. viii. 

 VOL. XII. — PART III. No. 1. — August, I8Sfi.=™„... L 



zi 



