168 RdTATORTA 



greater^than the aiitrrinr Ijrcacltli, twn posterior spines wliich arc iisualiy suliequal, or (Hie 

 asyninietrically i)lace(l spine, or without spines. 



f. platci ( J;igerskir)kl). Posterior spines long, strongly divergent basally, bent ruund so 

 thai apically thev lie at right angles to the long axis of the body. An e.Kiiberant development 

 of f. divergetus from the Baltic. 



f. dh'crgcns (Voigt). Posterior spines long, more than half the length of the lorica 

 (excluding anterior spines), subequal and strongly divergent, reticulate and punctate sculp- 

 ture well developed. Syn. var. longispina Thiebaud (1911). 



f. frcnzcH (Eckstein). Posterior spines more than lialt' the length of the lorica. Sub- 

 equal and somewhat sinuate, but with parallel axes. Sculpture practically absent. 



f. qiiadrata (Miiller). Posterior spines alxmt half the length of the lorica, su1)equal, 

 and subparallel, reticulate and punctate sculptare well developed. 



f. testudo (Ehrenberg). Posterior spines short, about one-seventh of the length of the 

 lorica, often somewhat divergent. Punctate and reticulate sculpture both present. 



f. bmnspina (Gosse). Posterior spines short and equal as in testudo, often somewhat 

 divergent. Punctate sculpture absent. 



f. valgoides f. n. Right posterior spine well developed, left absent. Punctate sculpture 

 absent. Syn. z'alga Fadeev 1927, p. p. Wesen1>erg-Lund 1930 etc., nee. Ehrenberg. 



f. irrcgtilaris (Jakubski). One posterior spine (right in tj'pical figure) absent, the other 

 represented by a minute papilla. 



f. curvicornis (Ehrenberg). No posterior spines, punctate sculpture absent. 



Of the other forms described and probably referalile to this species, Auuraca squaunda 

 Ehrenberg is clearly a very reduced curuicornis without reticulate sculpture. However, it is 

 very doubtful that this is really the same as Brachionus squariuda Miiller, the anterior 

 spines of which suggest a very round reduced form of Nothoka striata, in all pr(jbal)ility the 

 use of this name is superfluous. A. falculata Ehrenberg and -i. qiiadridentata Ehrenberg 

 are doubtful forms which probably need not be recognised. 



In the Nilgiri Hills and in most localities in Kashmir (Figure 3 a, b) moderately devel- 

 oped forms that have rather divergent spines and may be regarded as transitional between 

 the typical form and f. (/;'trr^r«.y are common. Well-developed examples (Figure 3 c) of 

 the latter are found in the Ootacamund Lake (N 5). In Sundar Khun (K26), however, a 

 very well developed unsculptured form with long parallel posterior spines, which may be 

 referred to f. frcnzeli, is abundant (Figure 3d). No reduced fonns were found in any 

 samples from these regions. 



In the high lakes of Indian Tibet qiiadrata forms with moderately long spines, which 

 in the specimens from Tso Moriri and Tso Nyak in 'ril)et are fairly divergent ( l'"igure 3 e), 

 are found. In Tso Nyak the reduced f. valgoides (Figure 3 f) also occurs sporadically, while 

 in Mitpal Tso a form (Figure 3 h) referable to f. testudo is found though less commonly 

 than is f. quadrata. The specimens from Tso Nyak, and to a less degree from Tso Moriri, 

 are feebly sculptured, while the Mitpal Tso form which is rather wide and gibbous dorsally 

 has well developed sculpture and slightly convergent posterior spines. It is probably unwise 

 to attempt to correlate the occurrence of reduced forms in these cold elevated lakes with 

 ecological conditions without more knowledge of the seasonal cycle, but their occurrence may 

 be of significance. 



