ZOOLOGY. 597 



t| inches long, tlius exceeding- in size the corresponding part of any 

 other species and indicating the existence of a Holothurian larger than 

 any previously" known. [Quart. Journ. Mic. Sc, xxiv, pp. 255-261, with 

 pi.) 



WORMS. 



Rotifers. 



Classification of Rotifers. — A new classification of the Eotifers has 

 been proposed by Dr. C. T. Hudson, who, it is understood, has been 

 for souie time engaged in company with Mr. H. P. Gosse on a monograph 

 of the class. Twelve families are recognized and defined, and these 

 are segregated under four groups called " orders " and distinguished 

 chiefly by the mode of progression. At first sight this might seem to 

 be an unsafe guide, and it remains to be seen whether it will stand the 

 test of critical analysis. The ordinal characters and families are as 

 follows : 



"Order I, Rhizota," including fixed forms, with the foot attached, 

 transversely wrinkled, non retractile, and truncate. 

 Family 1, Flosculariidse. 

 Family 2, Melicertidse. 

 ''Order II, Bdelloida," including Rotifers "that swim and creep like 

 a leech," with the "foot retractile, jointed, telescopic," and with 

 its " termination furcate." 

 Family 3, Philodinidfe. 

 " Order III, Ploima," composed of Rotifers " that only swim." 

 Illoricatcd. 

 Family 4, Hydatinidfe. 

 Fa^nily 5, Synchoetidae. 

 Family 6, Notommatidae. 

 Family 7, Triarthridae. 

 Family 8, Awsplanchnidae. 



Loricated. 

 Family 9, Brachionidse. 

 Family 10, Pterodinidae. 

 Family 11, Euchlanidae. 

 " Order IV, Scirtopoda," embracing " Rotifers that swim with their 

 ciliary wreath, and skip by means of hollow limbs with internal 

 locomotor muscles. 

 Family IL', Pedalionidae." 



{Quart. Journ. Mic. Sc, xxiv, pp. 335-356; J. R. M. IS. (2), IV, pp. 

 748-750.) 



Platy helminths. 



Free-living Nemaioids. — The free-living fresh- water Nematoids of the 

 Dutch fauna have been investigated hy Mr. J. G. de Man, conservator 

 of the zoological museum of Leyden, and the results published in a spe- 



