46 JAMES MURRAY 



elongate than most of them, and in that respect comes nearest to P. erythrophthalma 

 Ehr. (15). The characteristic spurs, consisting of a narrow blunt apical portion 

 springing abruptly from a broad conical base, will separate it from that and all other 

 known species when well developed. Sometimes the narrow part is considerably 

 reduced. No other member of the genus has such spurs, but very similar spurs, 

 differing only in being sharper pointed, are possessed by Callidina hexodonta, Ber- 

 gendal (3), formerly regarded (from the possession of cervical eyes) as belonging to 

 the genus Philodina. 



The slender foot, which can be elongated much more than the drawing (Fig. 5a) 

 shows, the lack of interspace between the spurs, and the deep red stomach are 

 also good characters. 



Philodina alata, sp. n. (Plate X., Figs. 4o-4/) 



Specific characters. Size moderate : corona broad, diameter about equal to that 

 of the trunk (exclusive of the processes) in ordinary extension ; collar inconspicuous, 

 the lobes going to the upper lip not reaching beyond the line of the bridge joining 

 the pedicels : interspace between discs equal to diameter of disc ; central setae on 

 discs : teeth 2/2 : trunk plicate, bearing two large rounded lateral processes (one on 

 each side) a little way in front of the widest part of the central segments : rump 

 short, with a rounded boss in the middle of the preanal segment : foot short, four- 

 jointed, spurs diverging, tapering, conical, rather blunt. Eyes brown. 



General description. Length 300 /t, in the feeding attitude. The stomach is of 

 the same deep red as in P. gregaria, the colour being seated in small granules and 

 globules. The rostrum is short and rather narrow. The length of the antenna is 

 about equal to the diameter of the neck. On the fairly large brain are seated the 

 pale brown eyes. The jaws are rather small, and bear two teeth each. The trunk 

 is regularly plicate, the dorsal folds being wider and shallower than the lateral ones. 

 The trunk is sometimes decidedly viscous, and has extraneous matter adhering to it, 

 but this is not always so. It is sometimes quite clear. 



The lateral processes are not thickenings, like most of the trunk processes of 

 Bdelloids. They are large, hollow, approximately conical protuberances, with skin 

 no thicker than that of the trunk, unless at the extreme apex, where it is a little 

 thicker. They are controlled by special muscles, by which the apex may be more or 

 less pulled in and inverted, making the form truncate, as shown in Fig. 4a. Some- 

 times, when creeping or feeding, the processes are so far inverted that they are 

 scarcely visible in dorsal view, but this is not always the case, as shown in Fig. 4c, 

 where they are fully extended when the animal is creeping. In complete con- 

 traction of the animal they have their greatest projection, and are then more 

 directed forward than at any other times. 



No suggestion as to the function of these curious processes has been offered. In 

 other Bdelloids having warts on the body they are supposed to have a defensive 



