ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 53 



36-40 tentacles, the crown is almost funnel-shaped, with an inturning ai 

 the anal side ; the statoblasts are flat, circular, with an annular float, and 

 no marginal spines. 



Rotifera. 



Philodina macrostyla and its Allies.* — James Murray gives a 

 summary of all that is known of this interesting but difficult group, 

 notable for the extreme variability of some of the species. Seven for 

 and their varieties are figured. 



Notommata (Copeus) pseudocerberus sp. n.f — P. de Beauchamp, 

 having previously described as X. cerierus, a species which lie now finds 

 to be really new, gives a detailed account of the differences betwe* a 

 these two closely allied forms. 



Gelatinous Envelops in Plankton Rotifers.:]: -- R. Lauterborn 

 calls attention to the fact that Rattulus cylindricus Imhof (Masti- 

 gocerca set if ere Lauterborn), is surrounded by a large gelatinous 

 envelope, which is so transparent as to be invisible until brought out by 

 mixing Indian ink with the water. Of other free-swimming Rotifers 

 the author has found only Hudsondla pigmcea to have a similar, but 

 very thin gelatinous envelope, which swells up very greatly when the 

 animal dies or is killed and stained. We may add that Notops hyptopus 

 has a like envelope. 



Desiccation of Rotifers. § — I). D. Whitney finds that out of forty- 

 five different species belonging to seventeen families of free-swimming 

 Rotifers, only two, Philodina roseola and P. citrina could successfully 

 withstand desiccation and resume normal activities when again placed 

 in water. The author concludes that it seems probable that desiccation 

 of the adult Rotifers, followed by revival, is not of widespread occur- 

 rence in the group, and is not the means resorted to by most species for 

 tiding over unfavourable periods. Survival is due in most cases to the 

 winter eo-o- s which can withstand both desiccation and low temperature. 



Formation of New Colonies of Megalotrocha alboflavicans.[|— 

 Frank M. Surface gives a very interesting account of the formation of 

 new colonies of this Rotifer, showing quite complex instincts and 

 reactions to stimuli. The main features are as follows. When first 

 hatched from the eggs the young have a ciliated foot and two eyes and 

 are free-swimming^ but do not leave the colony singly. These indi- 

 viduals come together into a swimming ball, which reacts positively to 

 lisjht. Later, under certain conditions, particularly absence of light 

 stimulus, the ball breaks up into free individuals again. These then 

 aggregate themselves into a permanent fixed colony in winch - 

 animals spend the remainder of their lives, having lost the two eyi s and 

 the circlet of cilia at the foot. In this colony formation the mucus- 

 like secretion of the foot-gland plays an essential part. 



* Journ. Quekett Micr. Club., ser. 2, x. (190S) pp. 207-26 (3 pis.). 



t Zool. Anzeig., xxxiii. ( 1908) pp. 399-403. 



J Tom. cit., pp. 580-4. ' § Amer. Nat., xlii. (1908) pp. 665-- 1. 



II Biol. Bull. Univ. Pennsylvania, xi. (1906) pp. 182-92. 



