162 THE VICTORIAN NATURALIST. 



Proportion of greatest breadth of carapace to its median length, 



4:3- 



Length of carina compared with that of carapace, 2 : 3. 



Length from posterior end of carina to posterior angle of 

 carapace, 1 : 2. 



Length of carina compared with median length of carapace, 

 2:3. 



Carina minutely and irregularly serrated and ending in a spine 

 posteriorly. 



Sinus of the carapace with about 18 minute teeth on each side 

 of the mid line : sometimes rudimentary or absent in some parts 

 of the margin. 



Posterior outer margin of the carapace with minute serrations 

 which gradually become more minute on passing forward, until 

 they disappear at about half the length of the carapace. 



Dorsal surface of the carapace sparsely covered with irregularly 

 scattered minute blunt projections. 



Number of abdominal segments uncovered, about 29. 



Number of abdominal segments not bearing limbs, about 12. 



Each limbless segment of the abdomen with about 15 sub-equal, 

 short, conical spines, arranged in a single row, with numerous 

 smaller ones irregularly scattered over the under surface. 



The exposed limb-bearing segments with spines on the upper 

 surface and sides, becoming obsolete in the anterior segments. 



Telson a little less than twice as long as broad. 



Upper surface of telson with 3 or 4 median spines ; a spinous 

 posterior border and sides and 2 or 3 spines forming a group 

 on each side anteriorly. 



Lower surface of telson minutely spinulose, with a median and 

 two lateral depressions, free or nearly free from spines. 



Caudal appendages considerably longer than the median length 

 of the carapace. 



Second antennae absent. 



The 5 th endite of the 1st thoracic appendage varying much in 

 length. It may reach as far back as the 15th exposed abdominal 

 segment, or it may reach only to the posterior end of the carina. 



No difference in size or proportions between the males and 

 females. 



Total length of the largest male, from the anterior margin of 

 the carapace to the end of the telson, 70 mm. 



Total length of the largest female, 64 mm. 



Out of a total of 58 individuals, 6 are males, 52 females. 



Locality. — Central Australia. In waterholes at different lo- 

 calities between Oodnadatta and Charlotte Waters (W. B. 

 Spencer). A single specimen, collected by Mr. J. A. Kershaw, 

 was found near Kewell, Victoria, and has been kindly placed by 

 him at our disposal. 



