554 THE REV. T. R. R. STEBBIXG ON [May 26, 



2. Zoological Results of tlie Third Tanganyika Expedition, 

 conducted by Dr. W. A. Cunnington, 1904-1905.-- 

 Report on the Isopoda terrestria. By the Rev. Thomas 

 R. R. Stebbixg, M.A., FeR.S., F.L.S., F.Z.S.* 



[Received April 23, 1908.] 



(Plate XXVII. t) 



The small collection of African Land-Isopoda which Dr. Cun- 

 nington has asked me to examine includes only four species. Two 

 of these ai-e already known. The other two appear to require the 

 institution of a new genus. Whether the species for which it is 

 instituted are themselves new may be more open to question. 

 It is with much I'eluctance that I accept the responsibility of 

 offering a decision. In the balance of uncertainties one has at 

 last to make up one's mind. At present there are a bewildering 

 number of species in the genus Philoscia, many of them very 

 incompletely described, and few, if any of them, completely illus- 

 trated. A remedy for this state of affairs will not be easily 

 found. The creatui'es themselves put difficulties in the way of 

 the student. Their readiness to wander about the world under- 

 mines any systematic structure built on geographical distribution. 

 Their vaiiability seems to separate foi-ms which are specifically 

 identical. On the other hand, general resemblance seems to 

 unite forms which, on closer examination, are found to be 

 distinct. Among the appendages the antennae and uropods afford 

 especially useful chai'acters, and these appendages are particularly 

 liable to be detached or broken. The structure of the pleopods, 

 especially those of the male, is more and more acquiring 

 systematic importance, but male specimens are not always avail- 

 able. Fortunately there are naturalists to whom difficulties are 

 not discouragements so much as incentives to action. This paper 

 will serve at least some useful purpose if it should induce any 

 such investigator to deal effectively with the genus Philoscia and 

 its immediate allies. 



Fam. O N I s c I D .^. 



Gen. Metopoxorthus Budcle-Lund. 



1885. Metoponorthus Budde-Lund, Isopoda terrestria, p. 161. 



Metoponorthus pruinosus (Brandt). 



1833. Porcellio j^ndnosus Brandt, Conspectus Crust. Oniscod. 

 pp. 19, 26 (Budde-Lund). 



* [The complete account of the new genus diagnosed in this communication 

 appears here, but since the name and the preliminary diagnosis were published in 

 the 'Abstract,' the gijnus is distinguished by being underlined. — Editor.] 



t For explanation of the Plate, see p. 560. 



