862 Transactions of the Society. 



not see the eyes in the column. But when I looked to the pectus, they 

 were plain enough, though very pale, I know no other species, whether 

 of Botifer or Fhilodina, with so very small a corona in rotation. The 

 whole trunk is fluted. The viscera are tinged with pale smoke-brown, 

 deepest in the abdominal canal. In some examples the hue is rather of a 

 chestnut-brown. 



I have examined perhaps half-a-dozen specimens, inhabiting the 

 conferva of marine rock-pools in the Firth of I'ay. The species is very 

 shy of rotating, thus difiering from other Philodinm, which are 

 characteristically free. At the moment of extruding the column, its 

 broad extremity opens a central orifice {d), which is strongly ciliated 

 around its margin, while a row of cilia, apparently few and distant, 

 is seen fringing the outer edge. The antenna (e) consists of (two ?) 

 telescopic joints, its extremity dilated, carrying four divergent setae. 

 (Fig. 1, plate XIV.) 



2. Notommata Theodora. Near to N. aurita, naias, and potamis ; 

 from all which it difiers in that the eye is small, and quite frontal, while 

 the slender straight foot is protrusile to an immense length, or wholly 

 retractile. Length, when fully extended, about 1/60 in. Lacustrine. 



A noble form, of great elegance, and of glassy clearness ; colourless, 

 save for a tinge of pale-orange in the tissues of the head (frequent in the 

 kindred species), and the occasional hue of the contents of the stomach. 

 The body has the massive aspect of the species named, but the position 

 of the eye is notable, close to the frontal edge of an ample brain. The 

 form and extreme versatility of the foot, too, are quite peculiar. Some- 

 times the body is truncate behind, and only the tips of the tiny toes 

 are seen protruding from the hyaline cavity (c) ; when, with lightning 

 suddenness, the foot, like a slender rod of glass, is shot out to 

 a length equalling the whole trunk ; and so carried, while the animal 

 darts along with headlong swiftness. The only parallel to this, that 

 occurs to me, is the case of Rotifer macrurus. The toes are often 

 turned suddenly, to the right or left, at a joint just above them, the long 

 foot else preserving its perfect straightness. When smoothly swimming, 

 the front often appears as if auricles were on the point of developing, 

 but I have not seen them extruded. In retractation the front often 

 becomes pursed-in at the middle. (Fig. 2.) 



3. Notommata Umax. Body vermiform, integument soft ; alimentary 

 canal ample, thrown into apparent annulation by alternate constrictions 

 and swellings : brain having a globose terminal bulb partly filled with 

 opaque chalk-masses, and partly with a large eye : foot-bulb contained 

 within the body ; toes long, slender, acute, decurved. Length 1/173 in. 

 Lacustrine. 



The slug-like softness of the skin gives this species some resem- 

 blance to Biglena permollis ; but it is less versatile in outline. The 

 brain recalls N. aurita, the ample sac having a slender tube running 

 through it occupied with opaque specks, which terminates in an ovate 

 expansion. This is, in part, opaque with chalk deposits, and its rounded 

 extremity is filled by a large crimson eye (c). There is a likeness 

 to N. cyrtopus in the toes; but the general facies is very diverse. 

 Swimming it will suddenly augment its speed by pushing out for an 



