166 Transactions of the Society. 



F. regalis. (Plate IV. fig. 3.) 



Mr. Bolton sent me this remarkable rotifer last September. 

 Its trocbal disk is quite unique, for hitherto all the known species 

 of Floscules have had either five or three setigerous lobes. It is 

 true that Ehrenberg credits his F. inoboscidea with six lobes 

 and a flexible open-mouthed tube rising from the midst of them, 

 all crowned with setae, and says that he has found F. ornata 

 sometimes with five lobes and sometimes with six ; but hardly any 

 other observer has seen a six-lobed Floscule, 



Mr. Slack, in ' Marvels of Pond Life,' says that he has met with 

 F. ornata bearing six lobes, with "six hollow fan-shaped tufts 

 [of setae], one attached to each lobe." Dr. Dobie also states that a 

 friend of his, viz. Mr. Hallett of the Museum of the Eoyal College 

 of Surgeons, had found F. ornata " with a six-lobed rotatory organ." 

 Such precise statements ought perhaps to settle the question ; but 

 Mr. Slack goes on to say that "for a long evening only five 

 could be discerned in the specimen now described, but the next 

 night six were apparent without difiiculty or doubt," and he 

 attributes the discrepancy to the difierent positions which the 

 Floscule held. 



It is quite possible then that Mr. Slack had F. regalis under 

 observation, and not F. ornata, and that the creature's varying 

 positions hid now one, now both, of the smaller lobes. Ehrenberg's 

 F. lorohoscidea may have been also the same creature ; for though 

 Ehrenberg describes it as having a flexible snout-like tube with an 

 open mouth rising in the midst of the lobes, his figure shows 

 merely a well-developed dorsal lobe with a clear space near the 

 summit between its two surfaces. This clear sub-spherical space 

 exists in several species of Floscule, and Ehrenberg seems to have 

 mistaken it for the mouth of his " flexible tube." 



His figure bears rather the broadly-curved lobes of F. cam- 

 ^anulata than the knobbed ones of F. regalis, but he distinctly 

 says that the lobes were knobbed. Possibly there may yet be 

 another species of seven-lobed Floscule with flattened lobes ; at any 

 rate, I think it not unlikely that Ehrenberg had some seven-lobed 

 Floscule when he described F, jiroboscidea. 



The mouth-funnel of F. regalis is a deep cup with a nearly 

 circular rim, from which project four knobbed processes on the 

 ventral side, dividing that half of the rim into three equal spaces. 

 They curve shghtly outwards and widen as they approach the rim, 

 so that their bases unite, and give to the edge of the cup a hexagonal 

 appearance. 



On the dorsal surface rises a large triangular knobbed lobe 

 bearing on each side of its base two very short recurved knobbed 

 processes. All the seven knobs carry pencils of long radiating setae. 



