Fresh-water Entomostraca of South America. 65 



deflexed. Surface of shell perfectly smooth, without any 

 perceptible sculpture, lower edges of valves finely ciliated, 

 the ciliation, in the posterior half, occurring somewhat within 

 the margin, infero-posteal corners armed with a distinct, 

 someAvhat upturned denticle. Ocellus smaller than the eye. 

 Lip-plate large and quite smooth below. Caudal part com- 

 paratively narrow, upper corner carrying the caudal setæ, 

 remarkably thickened, supra-anal projection distinct, being- 

 defined both above and below by a sinus, lower corner 

 rounded and not produced, marginal denticles well marked, 

 numbering about 12 on each side, no lateral denticles pre- 

 sent, caudal claws comparatively short and curved, each with 

 2 strong denticles at the base. Colour greyish white, pel- 

 lucid. Length of adult female 0.34 mm. 



Remarks. — This "also is a very distinct and easily 

 recognizable form, being especially distinguished by the to- 

 tal absence of any sculpture on the shell, which appears 

 perfectly smooth and shining, even when out of the water. 

 The structure of the caudal part also is rather peculiar, and 

 together with a few other characters, exhibits, as it were, an 

 approach to some species of the genus Chydorus. 



Occurrence. — I found this form not unfrequently 

 in some of my aquaria prepared w T ith mud from Itatiba. 

 The specimens, which were all of the female sex, moved in 

 a pronouncedly jerky manner, and rather rapidly. 



Gen. Graptoleberis, G. O. Sars. 



Remarks. — This genus was long ago established 

 by the present author, to comprise the anomalous form de- 

 scribed by S. Fischer as Lynceus testudinarius, and has 

 generally been admitted by subsequent authors. No addi- 



5 — Archiv for Math, og Naturv. B. XXIII. Nr. 3. 

 Trykt den 16. Marts 1901. 



