424 Transactions of the Society. 



VIII. — On a New Species of Hydrosera ( Wallich). 



By Henry Stolterfoth, M.D. 



(^Read llth May, 1881.) 



Plate V., Figs. 2 and 3. 



A SHORT time since I received from a friend a small quantity of a 

 sub-peat fresh-water deposit from New Zealand. This material 

 proved most interesting, and contains forms differing considerably 

 from any found in Europe. Many of these have been already 

 described by Mr. Kitton and others. My attention was arrested 

 by a curious three-lobed form, which I could hardly recognize as a 

 fresh-water diatom. It was not abundant, only one or two valves 

 on a slide, and it was not till I obtained a front view of the valves 

 that I was certain that I had a diatom. 



I have placed it in the genus Hydrosera as the nearest I could 

 find, although as to certain particulars it does not altogether agree 

 with the genus as described in Pritchard's ' Infusoria,' 4th edition, 

 p. 852 ; still in many respects it resembles S. triquetra (Wallich). 



Description of Species. 



Hydrosera tricoronata n. sp. Filamentous. Front view of 

 valves nearly quadrangular, showing four ridges and a deep central 

 depression, distinct connecting band; side view trilobate, each lobe 

 having three projections or minor lobes. The lobes are finely 

 dotted, no regular markings on the central hexagonal portion (cf. 

 Figs. 2 and 3). 



Habitat. — North Canterbury, New Zealand, in a sub-peat 

 fresh-water deposit. The exact locality not known. 



