lis HALF-AN-HOUR AT THE MICROSCOPE. 



EXPLANATION OF PLATES XIIL AND XIV. 



Plate XIIL 



Figs. Ij 2, and 3. — Aregma hulbosum, from specimens on the slide 



under examination. 



Fig. 1. — p.s., J9..S. , protospores — bulbilli, or buds thrown off in the 

 early stage of the plant, and capable of independent growth. 

 The letters in sequence, a to e", illustrate the process of deve- 

 lopment, and the sequence of changes therein. 



a, Swollen termination of a branch, with colourless granu- 

 lar contents, a' shows mapping out of these contents into 

 what will afterwards become the four " endochromes," that 

 being the normal number in this species. At c.d. the walls of 

 the spore are seen acquiring a brown colour ; the part which 

 is farthest from the seat of attachment being the earliest and 

 most advanced, as indicated by the increasing depth of 

 colour. 



2. — Developing spore, seen with a higher power, to show how the 

 spore is formed, as are " asci " in the ^' Ascigerous Fungi,'' and 

 the formation of pearly beads by nodular corrugations of the 

 outer cell-wall. 



3. — The same facts illustrated in diagram, sp., sp., spermatia. 



4. — Aregma macromatum, from the Rose. 



5. — 5, hulbosum, from the Bramble. This figure was taken 

 from a freshly-gathered specimen, and has the " pearly beads " 

 well developed. 



6. — Aregma gracilis, from the Raspberry. 



7. — ,, obtiisatum, from the Barren Strawberry, Potentilla 

 fragariastrum. 



8. — Triphragmium Vlmarice, also showing the pearly beads. 



3) 



3) 



J) 



)) 



Lower PonTioisr — Diagrammatic Sketches. 



Fig. 1. — Tongue of Snail, showing — a, Tooth by which the leaf is 

 held whilst being eaten ; b, Muscle for drawing the tongue 

 up ; c, Muscle for drawing it down. 



2. — Tongue of Snail, seen from above. 



3. — Ditto Periwinkle. 



4.— Ditto Whelk. 



5. — Flagellated Spermatozoa of Oyster. 



6. — Early stage of same before the formation of tails. 



J) 



Plate XIV. 

 Illustrating Tortoise-Tick. 



The Figure in the upper portion is a fac-simile on a smaller scale of 

 a drawing made by me (Tuffen West) many years ago, the original 

 drawing from which it was taken being x 25 diameters of Tortoise- 

 Tick. 



