50 A Rotifer New to Britain. 



though I could not trace its history. * Including' should certainly 

 have been 'inclosing,' as you suggest." 



In Mr. Slack's " Marvels of Pond Life," p. 149, he has 

 described and figured a tubicolous Rotifer, with a very long 

 antennal projpess. He considered it to be Limnias ceratophylli, 

 but noticed the discrepancy between the form of the trochal 

 disk in my figure of that species in "Evenings at the Microscope," 

 and that of his animal. Having intimated to this gentleman 

 my suspicions that the creature wag neither Limnias, nor any 

 other with which I was acquainted, he was so kind as to send 

 me from time to time a number of specimens, all found in 

 considerable abundance studding the stems and leaves of Ana- 

 charis alsinastrum — a pond-weed which, Mr. Slack tells me, is 

 fast displacing all other sub-aquatic vegetation in the waters 

 about the north of London. The examination of the specimens 

 thus transmitted, has confirmed the suspicion of its novelty to 

 us, and has convinced me of its identity with the Berlin genus 

 Cephalosiphon, and probably with the species 0. limnias. This 

 identification I shall, at least for the present, assume. 



The animal manifests a very close affinity with (Ecistes, 

 Limnias, and Melicerta ; in the form of its petaloid disk coming 

 between the last-named two ; for the outline of this organ (see 

 Fig. a) may be described as two-lobed, with each of the lateral 

 lobes having a tendency to divide into two ; the entire form 

 having a striking resemblance to the expanded wings of a 

 butterfly, such as our little Orange-tip, for example. In the 

 antenna, distinctness from each of the genera named is mani- 

 fested, for while Melicerta has two rather long antennae, Limnias 

 two reduced to mere bristles, and (Ecistes none at all, our Cejoha- 

 losiphon displays a single one, of extraordinary length and 

 versatile power. Like Melicerta and Limnias it shows no visible 

 constriction or neck below the disk, whereas in (Ecistes this is 

 a conspicuous feature. 



The animal inhabits a case slightly trumpet- shaped, generally 

 of great length and slenderness, compared with those of its 

 allies, standing erect on the pond-weed. It is irregular and 

 floccose in outline, very opaque, and of a deep bistre or umber 

 brown by transmitted light, but of a much lighter hue, cedar- 

 brown, by reflected light. It is composed doubtless of an 

 excretion from the skin as the foundation layer, thickened and 

 opacified by the addition of the dark material, which I con- 

 jecture to be the faecal pellets successively discharged in process 

 of growth. Yet I must confess I have never seen the stomach 

 or intestine charged with dark brown food, in any of those that 

 I have examined, which have certainly been but few, in a healthy 

 active condition. 



Contrary to the rule in the allied genera, the petaloid disk 



