THE VICTORIAN NATURALIST. 



the genus Conochilus, most probably undcscribed. This later 

 visit was induced by the discovery of a species of Pedalion. This 

 interesting rotifer when first discovered by Dr. Hudson necessi- 

 tated the creation of the order Scirtopoda, and now there are 

 only two genera known, Pedalion and Hexarthra, containing 

 respectively two and one species. Pedalion is mentioned as very 

 rare. It has been noted by members of the Club previously, but 

 only in small numbers. Subsequent visits have proved the 

 " Springbank " pool to swarm with Pedalion for a period of six 

 weeks. As is well known, the chief interest of this form is that, 

 while possessing the most distinctive anatomical features of a 

 rotifer, it is furnished with six limbs, controlled by a remarkably 

 developed muscular system, and each provided with tufts of 

 plumose setse almost precisely resembling those possessed by 

 members of the class Crustacea, such as are found in the orders 

 Cladocera and Copepoda. The Pedalion found differs from the 

 two described species, and further study of it may possibly show 

 that its peculiarities entitle it to rank as a distinct species. 



The lagoon near the bridge over the Yarra was examined on 

 the way back, and was found covered with Lemna and Azolla. 

 The gathering from this pool, though hastily made, proved pro- 

 ductive of an assemblage of forms of Rotifera so diverse in their 

 anatomy that they might well have been selected as illustrative 

 of the great variations in form characteristic of the group : 

 Notops clavulatus, sac-like, soft-bodied, and transparent ; Rotifer 

 macruras, short and worm-like ; Aclinurus neptunius, swimming 

 about like the common Rotifer vulgaris until some unknown 

 stimulus provoked the extension of its twelve-jointed telescopic 

 foot, thus increasing its length five-fold, and revealing a curious 

 tripod of toes ; Notens quadricomis, displaying an oval sculptured 

 and tesselated lorica, furnished at either extremity with projecting 

 spines; the beautifully translucent Pterodina palina, with a flattened 

 lorica; Diglena biraphis, representing the illoricate free swimmers ; 

 Brachionis bakeri, a loricate species so variable in the develop- 

 ments of its chitinous armour that Mr. Rousselet has been able to 

 demonstrate the existence of a gradation so evenly stepped that 

 some seven or eight specific names are wiped out, and the forms 

 reduced to varieties of the one species. Finally, Salpina eustala, 

 possessing a compressed lorica, with a curious groove running 

 down its arched back. Mr. Tisdall succeeded in identifying a 

 number of aquatic plants, and exhibits specimens preserved in 

 formalin. He says : — " On the surface of the backwater floated a 

 number- of water lilies, Ottelia ovalifolia, the beautiful white 

 blossoms contrasting well with their pretty oval leaves. The 

 water near the bridge was completely covered as with a green carpet 

 with the tiny Duck-weed, Lemna minor, interspersed here and 

 there by small brownish patches of Azolla fliculoides. In both 



