ArKiL 1, 1866.] 



SCIENCE-GOSSIP. 



b7 



SIMPLE OBJECTS.— No. XII. 



ACTINOPHRYS EICIIORNII. 



THE figures below represent an Aetinophi A J s > 

 most resembling the Actinophnjs Eichornii, as 

 given in the " Micro-graphic Dictionary ;" * only in 

 the present instance the animal seems larger, whilst 

 the tentacles are much smaller in proportion. The 

 body of the animal is spherical and opaque, and 

 surrounded with a transparent cellular network ; 

 from every angle of which springs a delicate hair- 

 like tentacle, the length of which is about one- 

 quarter of the diameter of the body. Within each 



Fig. 89. 



Figs. A and B, magnified 100 diameters. 

 Figs. C and D, magnified 2*8 diameters. 



cell, and apparently near the surface, are small black 

 granules (fig. C), which are in continual motion. 

 The surface also shows occasional protuberances 

 (figs. A, B a), which perhaps perform the office of 

 mouths. The members of this family are said to 

 draw into themselves, by means of their tentacles, 

 any small organism, as a diatom, which may become 

 entangled in them ; and gradually to press it through 

 the external covering, until it enters the body, 

 where its nutritive parts are extracted, and the rest 

 ejected by a reverse process to that by which it was 

 drawn in (fig. B c). 

 In some individuals numerous vacuoles occur 



* Plate 23, fig. 7a. 



(fig. B), some of which contain dark-coloured matter, 

 which is possibly the creature's food in various 

 stages of digestion, as the occurrence of a diatom in 

 one of these would seem to indicate (fig. B, b). 



J. S. Tute. 



A T 



GENERA OF DIATOMS. 



page 62 we illustrated four genera of Diatoms. 



The four remaining genera of the Navicular 

 group, with free frustules, coutain but 

 comparatively few species. 



Toxonidea has the valve elongated, 

 convex, with the sides unsymmetrical, 

 oblique stria;, and a longitudinal curved 

 (or arcuate) line, the ends and terminal 

 nodules of which curve towards the 

 same side of the valve. We have only 

 about two species (fig. 90, Toxonidea 

 Gregoriana x 400). 



Donkikia. — So called in honour of 

 Mr. Donkin, the discoverer of several 



Fig. 90. Toxonidea 

 Gregoriana. 



Fig. 91. Donkinia 

 carintita. 



new species. Has the convex valve keeled with 

 sigmoid median line, and fine decussating stria;. 



Fig. 92. Amphiprora 

 maxima. 



Fig. 93. Diadesmis 

 Willi'jmsonii. 



The front view is fiddle-shaped, and as broad as the 

 side view. There are about six British species (fig. 91, 

 Donkinia carinata, front and side view, x400). 



