72 MK. GEOFFREY WATKIN SMITH ON THE 



species of Phreatoicus, so that it is probably a characteristic of the whole suborder. 

 The alimentary canal is supplied with four hepatic caeca, which lie ventrally and open 

 at the base of the gastric mill. 



A pair of very large maxillary glands are present. 



The above points in the internal anatomy of the Phreatoicidea confirm the opinion 

 that they constitute a rather isolated suborder of the Isopoda, but does not lend support 

 to the view that they are related to the Amphipoda. 



Phreatoictjs atjstralis, Chilton, Records of the Australian Museum, 1 & 2, 1890-95, 

 p. 149. (PI. 12. fig. 1.) 



The thoracic segments are not much sculptured or tuberculated, and carry very few 

 spines dorsally. 



The head is as long as the two following segments. 



The second antenna has the peduncle and flagellum rather short, and the former has 

 the margin of only the first two joints serrated (PI. 12. fig. 9). 



The telson and uropod have the forms shown in PL 12. fig. 2. 



The colour is uniformly black and the length about 10 mm. Occasionally yellowish 

 specimens occur. 



Occurrence. Recorded by Chilton from Mt. Kosciusko and Thomson from 

 Mt. Wellington. I have taken it in the small pools on the top of Mt. Wellington, in a 

 small stream at sea-level at Huntingfields, and in a lagoon at sea-level on Bruni Island. 

 Also in Yule's Lake on the top of Ben Lomond and in the littoral region of the Great 

 Lake. The uropod differs slightly in the arrangement of the spines from the various 

 localities. The Ben Lomond (PI. 12. fig. 3), Great Lake (PI. 12. fig. 2), and the specimens 

 from the other localities (PI. 12. fig. 4) form three different varieties. 



Phkeatoicus spinosus, sp. n. (PI. 12. fig. 7.) 



The head is shorter than the two following segments. 



The body is markedly sculptured, and the thoracic segments bear two distinct 

 tubercular ridges dorsally with a concavity between them ; the abdominal segments are 

 also ridged. All the segments are furnished very richly with long and conspicuous 

 spines dorsally, and the legs are also covered with long spines. 



The second antenna (PI. 12. fig. 11) has the peduncle and flagellum very long, only 

 the first two joints of the peduncle having a serrated margin. 



The telson ends in a long projection and the uropods are also very long (PI. 12. fig. 8). 



The colour is blackish grey, with the extremities of the antennse and often of the limbs 

 bright orange. 



Length up to 25 mm., but also adult at 15 mm. 



Occurrence. Among weeds in the littoral region of the Great Lake. 



