THE YOUNG NATURALIST. 



341 



a minute vesicle of cellular tissue. As it 

 grows, this vesicle becomes divided into 

 others, and enlarges until it forms a minute, 

 green, leaf-like germ-frond, called a pro- 

 thallus, from which the axis, and its roots are 

 subsequently developed. 



(To be continued. J 

 "Our young readers are requested to pay 

 careful attention to the technical terms in the 

 foregoing paper. They are printed in italics, 

 and are explained in every case. If they will 

 take the trouble to master these now, they 

 will not puzzle them afterwards. — Eds,] 



CONCHOLOGY. 



LAND AND FRESH-WATER SHELLS. 

 By H. T. Robson, Stockton-on-Tees. 

 ( Continued from page 311 .) 

 FAMILY, AURICULACEA. 



Genus, Carychium. 



This genus has only one British species, 

 the shell resembles that of Zua in form, but 

 it is toothed in the aperture ; the animal has 

 the eyes at the base of the tentacles, towards 

 the hinder part, and at the outer side, there is 

 only one pair of tentacles, and they are short 

 and thick. The specie is named Minimum. 



Minimum. — As the name implies, this 

 species is exceedingly small, the shell 

 measuring scarcely a twelfth of an inch in 

 length, it is white and glassy, oval, with a 

 pointed spire, the aperture has three teeth. 

 It is found in damp places, among moss, at 

 the roots of grass, &c. 



Genus, Ccnovulus. 



The shells of this genus are somewhat 

 spindle-shaped, having the spire pointed, and 

 the base narrow though rounded, the aperture 

 is toothed. The animal has only one pair of 

 tentacles, at the base and inner side of which 

 are the eyes ; they breathe air, but are fcund 

 in wet or marshy places near the sea, where 

 the water is brackish. The species are 

 Denticulatus, Myosotis, and Bidentatus. 



Denticulatus. — The shell is about a 



quarter of an inch long, white, with a yellow- 

 ish brown epidermis, the aperture is rather 

 long and narrow, and has several teeth within 

 it on both sides. They are found on he 

 banks of rivers near the sea, in the south a:ul 

 south-west of England. 



Myosotis. — This is slightly larger than 

 the last, yellowish white, covered with a 

 brownish epidermis, it has four teeth on the 

 columella side of the aperture, but none on 

 the lip. This is also found about the mud 

 above high-water mark, at the sides of rivers, 

 near the sea, in the south and south-west of 

 England. 



Bidentatus. — This shell is white, and 

 the epidermis is paler thau the others of ihe 

 genus, it is also smaller than either ; in the 

 aperture there are two teeth on the columeila, 

 one of them distinct, the other less so, the 

 lip is without teeth. They are found in 

 various situations about river mouths, and 

 are rather more widely distributed than the 

 others. 



{To be continued.) 



BRITISH BUTTERFLIES. 



By J. E. Robson ; with figures from life by 

 S. L. Mosley. 



(Assisted by Contributors to the Y. N.) 



12, PAPHIA, Linn. PI. 7, Fig. 1. 



The Silver-washed Fr Hillary . 



" Paphia, a surname of Venus ; from the 

 island of Paphos." — A. L. 



Imago. — Plate 7, Fig. 1 . Upper and under- 

 side fulvous, with black streaks and spots. The 

 female is paler, and without the black streaks. 

 Underside : fore wing paler fulvous, with a few 

 black spots; hind wing greenish at the base, and 

 two rows of greenish spots between the veins 

 beyond the centre. The remainder of the 

 hind wing is silvery ; there is a wavy narrow 

 silvery band across the centre, a broader cne 

 near the base, but not passing the centre, and 

 a silvery line still nearer the base. The 



