^j'P'j' ] Raff, Notes on the Isopod, Phreatoicopsis terricola. 71 



of the sockets into which the proximal ends ol the pereiopods 

 fit. Figure i shows roughly the position of the plates as seen 

 from the ventral surface. The bases of the first four pereiopods 

 of the left side only are shown. 



The appendages are all similar to those of the male, with the 

 exception of the second pleopod, which, in the male, carries the 

 penial filament (fig. 2). 



Figure 3 shows the shape of the second pleopod in the female. 

 It is of the usual form, consisting of endopodite free from setae, 

 and a two-jointed exopodite bearing long setae. At the base 

 of the exopodite there is a small plate fringed with setae that 

 seems to correspond to the epipodite of the third, fourth, and 

 fifth pleopods. 



Figure 4 represents the shape of the telson and the right 

 uropod, both of which are similar to those of the male. 



As regards the first pereiopod, I have noticed a certain amount 

 of variation in both the sexes. The one figured in Professor 

 Spencer's and Dr. Hall's paper shows a strong tooth on the 

 propodos and on the dactylos. Also, the meros is figured as 

 having its process inclined upwards. These points seem 

 generally to answer to the largest of the specimens in both 

 sexes. Others not quite so large have the appendage more 

 like that represented in fig. 5 of this paper, there being no 

 teeth on the propodos or dactylos. The meros also is slightly 

 different, the process being inclined downwards towards the 

 propodos, not upwards. In others, again, this process projects 

 horizontally. The downwardly inclined process seems to be the 

 most common. 



It is interesting to note the occurrence of this species in two 

 areas so isolated from one another as the Grampians and 

 Otways, which are about 100 miles apart. Between these two 

 mountainous regions there is the broad valley occupied by the 

 western volcanic plain, and to the south of this the coastal 

 plain. The Tertiary marine deposits forming this coastal plain 

 are found also in i)laces below the volcanic rock, and indicate 

 that the Otways were once isolated from the mainland as an 

 island.* 



The natural habitat of the animal is in forest country, and no 

 specimens have hitherto been found in this broad valley, which 

 is typically treeless and dry country. 



Explanation of Platk. 



Fig. I. — Portion of ventral surface of Phreatoicopsis terrimla (femnlc). 

 showing four pairs of brood plates. 

 Fig. 2. — Second pleopod of male. 

 Fig. 3. — Second pleopod of female. 

 Fig. 4. — Telson. 

 Fig. 5. — First pereiopod. 



* Hall, T. S., " Victorian Hill and Dale," p. 99. 



