of the Royal Physical Society. 337 



accumulation of green granules as in Stentor Ophrydium and 

 Vorticella, but is a transparent and uniform staining of the 

 sarcode — a lighter tint of that of the cell. 



In young specimens found growing amongst the second batch, 

 the lobes of the horse-shoe were blunt and short, and the ciliary 

 band placed at a little distance from their edges, as in fig. 4. 



L. hyalina. — Colourless ; lobes of rotatory organ wider and 

 blunter than those of L. viridis. Cell buried in the substance 

 of Atcyonidmm hirsutum, and therefore not seen. Found at 

 low-water, Granton and Queensferry. Not uncommon. 



L. atro-purpureus. — Colour of animal that of a mixture of 

 ink and water. Cell yellowish-brown. Probably a variety in 

 colour of L. viridis with which it was found. 



[Since the above was communicated to the Royal Physical 

 Society, I have learnt from Mr Alder that he has occasionally 

 seen L. viridis, and he has sent me drawings of specimens ob- 

 tained in autumn last near Tynemouth. In these the spiral 

 gullet does not appear. Mr Alder thinks that the animalcule 

 sometimes burrows in the shells which it infests, as I have 

 noticed in the case of L. hyalina. 



At fig. 5 I have given a sketch of Vagincola ampulla (Miil- 

 ler), which has a bilobed rotatory organ, and so far bears some 

 resemblance to Lagotia.] 



II. Vagincola valvata. (Mihi). (Plate XVIIL, figs. 6, 7). 



This marine animalcule was found growing plentifully on 

 the zoophytes and sea-weeds in one of my tanks. It resem- 

 bled Vagincola crystallina, an inhabitant of fresh water, ex- 

 cept in its being colourless, whilst V. crystallina contains glo- 

 bules of green matter. It possesses another remarkable dis- 

 tinction also from V. crystallina, in the presence of a valve (a) 

 situated within its cell, which shuts down in an inclined 

 position (b) over the animal as it retreats therein. On exa- 

 mining the valve in situ I found it to consist of a rigid plate, 

 imbedded in a thick layer of transparent sarcode, which lat- 

 ter was continuous at the lower end of the valve, with a thin 

 layer of the same substance, lining the whole of the interior, 

 and coating the upper part of the exterior of the tube. The 



