18G DE. C, CHILTON ON THE SUBTEEEANEAN 



be almost subcbelate ; in tbe female tbe fouvtb pair is simjjle like tbe preceding. The 

 statement that tbe first four are attacbed to tbe body at tbe anterior ends of their seg- 

 ments and the last three at the posterior ends, although true enough of tbe typical sjiecies, 

 required some modification in the case of P. australis, for tbe last three pairs in this 

 species are attached to the centres of tlieir segments, tbe epimera occupying almost all 

 the inferior margins, and tliis is also true in a modified degree of tbe other species. The 

 point that I wished to bring out would be better expressed by saying that the legs arc 

 divided into an anterior series of four and a posterior series of tbree, and this would apply 

 equally well to the tbree species. 



3. " Abdomen long " sbould perhaps read " pleon long " in order to be consistent with 

 tbe term " pleopoda " used afterwards. The term " uropoda " is again a very convenient 

 one to use in place of " sixth pair of pleopoda." 



4. Tbe j)eculiarities of tbe pleopoda, as shown in tbe descriptions given below, are, no 

 doubt, quite worthy of being mentioned among the characters of tbe genus, but they 

 cannot be observed without dissection, and so long as tbe genus can be sufficiently dis- 

 tinguished by other points more easily observed, there is no necessity to introduce them. 

 Perhaps some of them, sucb as tbe possession of an " epipodite," will prove to be 

 cbaracters of tbe family and not merely of the genus. 



Phreatoictjs assimilis, sp. nov. (Plates XVI. & XVII.) 



Phreatoicus typicus, Chilton, New Zealand Journal of Science, ii. p. 89 (March 1884). 



Phrealoicus typicus (pars), Thomson and Chilton, Transactions New Zealand Institute, vol. xviii. 

 p. 151. 



Specific di(tg)wsis. Body somewhat stout. Pleura of tbe second, third, fourth, and 

 fifth segments of tbe pleon very largely developed, much deeper than then- respective 

 seo'meuts ; tbe inferior margins somewhat sparsely fringed with small spinules. The 

 projection at the extremity of the telsou not much produced, broader than long ; upper 

 angle of its extremity sharp and tipped with a few setge ; lower angle rounded. Lower 

 antennee about half as long as the body ; peduncle with the fifth joint only about half as 

 long again as the fourth ; flagellum much longer than tbe peduncle. Legs stoutish, 

 with tbe joints somewhat expanded, all the pairs well supplied Avith setae. Lower lip 

 wdth each half ovate, with the extremity well rounded. Inner lobe of the first maxilla 

 rather narrow and with only four plumose setae at its extremity. 

 Colour. Translucent. 



Length. About half an incb (10 to 12 mm.). 

 Habitat. "V\'incbester, South Canterbury, in wells {D. L. Inwood). 



Detailed Description. 



Tbe following detailed description is mainly taken from a male specimen that was 

 dissected for tbe purpose. A few points regarding tbe surface of tbe body &c. have been 

 taken from a female specimen that was mounted dry on a slide. 



Body (PI. XVI. fig. 1). Tlie female specimen has tbe body 10'5 mm. long, and tbe perceon 

 about 1'5 mm. deep. The body is of uniform breadth throughout its whole leugtb. In 



