RECENT BRITISH OSTRACODA. 



381 









: . 



"o-landulse mucosse," constitutes a very considerable portion of the contents of the mal 

 carapace. It should be noted that the " bursa copulatrkv" as well as tin 1 testis, is a 

 double organ, one on each side of the median line. The two bursa? lie closely in appo- 

 sition, but are not in organic connexion except at the upper margin, where they are 

 held together by a ligamentous tissue. The postabdominal rami are long and slender, 

 and terminate in two unequal slender claws and a short seta. 

 Length -^ in., height -§V in. 



Notodromas monachus is generally distributed throughout Britain, occurring often in 

 ery great abundance. It seems to delight chiefly in grassy pools, or lakes Avhere there 

 i a profusion of vegetation. Mr. Norman tells me that in sunny weather he has often 



it floating on the surface of the water in considerable numbers. Dr. Baird 





d 



the neighbourhood of London and Hugby as localities for this species. It has be n take 

 by Mr. Norman and myself in many places in the counties of Northumberland an 

 Durham ; and I have also met with it frequently in the lakes of Selkirkshire, Dumfries- 

 shire, and Kirkcudbrightshire. Mr. Robertson has taken it in the island of Cumbrae. 

 The following remarks of Mr. Kins* relative to the habits of the Australian species 



g JL UXLLOil J±& \J± -LT-i-i. ^-i"^ 



" Newnhamia fenettrata," are very interesting when considered in reference to those of 

 N. monachus :—" This very common hut interesting species lives almost wholly near 



the surface of the water, its boat-like plate enabling it to walk along the under surface, 



while its eyes, directed downwards, give immediate notice of the approach of an enemy. 

 When alarmed, it immediately sinks to a little distance, and then swims off, only coming 

 to the surface when all becomes tranquil. The hand passed over the water near the 

 surface, so as to intercept the light, or the surface being disturbed by the slightest 

 breath, instantly alarms them. They are the most active when the sun is sinning; and 

 often a whole troop of them may be noticed swimming round and round, and in and out, 



graceful motion, about an inch beneath the surface, in some spots 

 more favoured than others by the warmth of the sun. 



most livelv and 



Genus 5. Caxdona, Baird 



Like <**. except that the lower nnt — f— - J£* ^ T«Z 



second pair of jaws are destitute of a ta*^ S ^ ^ ^^ from 



short. Above the base of the postabdominal ram (to* ^ l ^ 



an enlarged base, somewhat similar to, but smaU« £«.«-* ° ^2 and 



XXXVII. fig. 2 .)• The auimals belonging to Jh^us "the bottom, or « the stems 



are very sluggish in their movements, craw hug leisuieiy 



of water-plants, or sometimes burying themselves in the mud. 



in , roi + o YYV fi-s 20-25, and Plate XNXVI. fig. 12.) 



1. Canbona albicans, Brady. (Plate XXV. fig* A ^ ^ 



Candona albicans, Brady, Ann. & Mag. Nat. Hist. vol. «*.<!**) p. U, P 



Tyneside Nat. Field Club, vol. vi. p. 107, pi. m. figs. 6 1. cons iderablv 



xr i i Qn „nl in heififht throughout, the leit consiaeraoiy 



Valves oblong, subreniform, nearly equal m lei 



overlapping the right ; height equal to more than half the ten, 



* 



vL Roy. Soc. V.a Diemc's UnJ, ™1. H. part 1 



