THE VICTORIAN NATURALIST. 115 



its helmet. It consists of two movable pieces that can be shut 

 down when the head is drawn in. A bright red eye is set at the 

 front of the mastax. This handsome Rotifer is no less' hardy. 

 We have kept one on a slide for more than a week, giving it only 

 a fresh drop of water each day. Playing about the weeds we see 

 representatives of the beautiful genera Euchlanis and Salpina ; 

 but our attention is distracted from these to a Rotifer, smoothly 

 gliding, that bears an unusually broad shield. Should it kindly 

 anchor itself in clear water we shall find in this most transparent 

 creature, Pterodina patina, a charming sight. Its lorica, all but 

 circular in form, consists of an upper and a lower plate, greatly 

 flattened, and united at the edges, but swelling out towards the 

 middle, so that a concavity is formed for the animal's body. This 

 concavity continues to the front of the lorica, and here we see the 

 slightly protruding head, with its corona of two circular lobes and 

 its pair of eyes. From a posterior opening, well under the dorsal 

 plate, a thick wrinkled foot issues. This terminates uniquely in a 

 ciliated cup. The gastric glands are the most striking internal 

 parts. They resemble two long streamers, spreading out, one 

 each side of the stomach. The Pterodina unites in itself some 

 characters of all three orders, having the thick wrinkled foot of 

 the first, the double rotating wheels of the second, and the lorica 

 of the third. Some of its muscles show a coarse striation. The 

 second drawing of this animal exhibits its grotesque appearance 

 as seen from the side. The dexterity displayed by this Rotifer 

 in making way through thick masses of algae is surprising, in view 

 of the wide spread of its lorica. A second species of the same 

 genus inhabits our pond. It presents in a marked manner the 

 features of P. reflexa, as described and figured by Hudson and 

 Gosse in the supplement to their work. Now we may see, 

 tearing through the water with fierce impetuosity, the strongest 

 swimmer that has yet appeared. This is taker's Brachionus. In 

 the genus Brachionus the lorica is broad, deep, and roomy, 

 narrowing slightly towards the front and variously shaped at the 

 back. Prominent spines adorn the front edge of the dorsal 

 plate. Baker's Brachionus has six of these spines. The central 

 and longest pair curve outwards, enclosing the dorsal antenna 

 between them. The corona bears several prominences, crowned 

 with strong setae, and is rounded at the sides into circular lobes. 

 The ciliary wreaths around these form two handsome wheels. 

 The whole internal economy is perfectly displayed, the lorica 

 being beautifully transparent. A large eye, crimson rather than 

 red, is set on the brain. The hinder part of the lorica is so cut 

 out that two strong lateral spines are formed. In the wide gap 

 between these we see the foot — thick, wrinkled, flexible as an 

 elephant's trunk, and terminating with two small toes. It can be 

 entirely withdrawn into the body. In the same wide space, and 



