HORN EXPEDITION — NARRATIVE. 133 



Some few miles to the east we eame upon the lagoon whieii is in reality only 

 a clay-pan. At the tini(3 of our visit, that is during the dry season, it was still uf 

 considerable size being about a quarter of a mile wide and three-quarters of a mile 

 in length, but the indications of flood on the sui'ioundin" Hats show that in the 

 rain season it must be of considerable extent. It is simply a shallow depression 

 between the two ranges — not more than at most five feet deep with a clay-sand 

 bed serving to retain for a time the water which drains into it as there is no outlet 

 eitlier east or west. Water beetles were darting up and down in tlu; muddy water 

 and in the main lagoon Es/hcria packardi \f'\th. its blood-red appendages was to Ijc 

 seen but not a trace of the larger form [Li/nnadopsis sqia'rei) alive. Even the 

 empty carapaces were quite confined to the dried up and scrub covered flats to the 

 south and east of the lagoon, and there they were abundant. We could not even 

 find a dried carapace of an x\pus, in fact the only ones secured during the 

 Expedition were two dilapidated specimens found by Mr. Watt and myself during 

 our I'cturn joui'ney along the Stevenson Creek, but as the termination of the 

 abdomen was wanting it was impossible to say whether they had belonged to the 

 genus Apus or Lepidurus. 



We were very disappointed at not securing the Estheria-like animal alive 

 but collected a number of the carapaces though these alone were not sufficient 

 for purposes of identification. Fortunately as previously said I secured a few 

 specimens of the entire animal during my subse(juent visit to Charlotte Waters 

 just after the rains had fallen, a year later, and then also obtained another closely 

 allied species of which not even the carapaces were to be seen at Conlin Lagoon. 

 Though Mr. Squire has carefully searched for the animal in the same spot during 

 the two recent sea.sons he has not been able to find a single living specimen. The 

 aniuuil belongs to a new genus closely allied to Estheria and Linuiadia and has 

 been described by Mr. Hall and myself under the name of Li/nnadopsis sijiii/ei, 

 the other species secured along the Stevenson being called L. tatci. The genus 

 is not however confined to the central region as Professor Tate had previously 

 collected a few carapaces of another species (Z. bninneus) in the Northern 

 Territory. 



The periodicity of occurrence of certain animals in this central area of the 

 continent has already been alluded to and is well shown in the case of Liiuna- 

 dopsis. Amongst the Crustacea there are certain species which always seem to 

 be obtainable after rain and certain othei'S which are not so certain to appear in 

 any particular spcjt, though they nuiy previously have been collected there in large 

 numbers. 



