i897-9 8 -] The Upper Elf Loch, Braids. 377 



as " frequent," while Simocephalus is described as " few." 

 When, however, the records of the gathering collected on the 

 26th of June 1897 are examined, it is found that Daphnia 

 is now in the minority, and is described as " rare," while 

 Simocephalus is " frequent." On the other hand, both species, 

 in the gathering collected in February last (1898), are de- 

 scribed as " rare." In addition to this apparently alternating 

 increase and decrease in the numbers of certain species — an 

 alternation which is probably due to seasonal variation — 

 another interesting feature in the distribution of the Entomo- 

 straca has been observed, which it may be worth while to 

 notice here. It was stated in our preliminary report, pub- 

 lished last year, that a somewhat rare copepod known as 

 Moraria Anderson- Smithi had been obtained in the Upper 

 Elf Loch. The first time this copepod was observed here 

 was on October 17, 1896 : it was again noticed in the 

 gatherings collected on March 6, May 1, and June 26, 1897, 

 but though it has been carefully searched for in subsequent 

 gatherings, no trace of it, alive or dead, has been found. We 

 cannot ascribe the disappearance of the copepod in these 

 subsequent gatherings to any difference in the mode of collect- 

 ing them, for the same method has been as far as possible 

 adhered to throughout the whole series of visits we have 

 made to the loch ; and, on the other hand, we would hardly 

 venture to assert that because we had not found this species 

 in these gatherings it had therefore become extinct ; but we 

 think it is quite safe to say that, if it still exists in the loch, 

 it must have become exceedingly rare. Moreover, if the 

 appended tabular list of the Entomostraca obtained in the 

 Upper Elf Loch, be examined it will be further observed that, 

 shortly after the disappearance of Moraria Anderson- Smithi, 

 another comparatively rare copepod — Canthocamptus inornatus 

 — was obtained for the first time. This species, which occurred 

 in the gathering collected on September 11, 1897, had only 

 a few months previously been described by one of us as new 

 to science, from specimens found in a loch in Forfarshire, and 

 also in Linlithgow Loch. How this species happened to be 

 introduced into the Upper Elf Loch, or, if usually present 

 there, how it came to be so long overlooked, are questions 

 more easily asked than answered. Canthocamptus inornatus 



