890 THE YOUNG- 



two valves. 



Genus 16, Osmuncla. 

 Marginal-fruited ferns, Having valved spori- 

 cases in irregular, dense .branching clusters 

 terminating the fronds. Comprises Regalis 

 only. 



Osmund a Regalis.— This noble-look- 

 ing fern grows from i to 4 feet high. Stipes 

 reddish when young. Fronds lanceolate, 

 bipinnate ; the pinnae ovate-lanceolate ; 

 pinnules oblong-ovate with serrate margin. 

 Spore-cases are subglobose, stalked, reticu- 

 lated, and valved. Found in marshy and 

 boggy situations. It is common. 



Group III, Ophioglossaceee. 



This group is composed of ferns having the 

 fronds folded up straight, the spore-cases 

 destitute of an elastic ring, aad two-valved. 



Genus 17, Botrychium. 



Marginal-fruited ferns, having the spore- 

 cases in irregularly branched clusters, on a 

 separate branch of the frond. Comprises 

 Lunar ia only. 



Botrychium Lunaria (Moon wort) .— 

 This peculiar, almoststemless plant, furnished 

 with a few coarse fibres and a bud springing 

 from the point which represents the stem. 

 The fronds grow from 3 to 8 inches high ; the 

 stipes constitutes the lower half of the smooth, 

 hollow stem. The frond is separated into 

 two branches, one pinnate and oblong ; pinna 

 cresent-shaped, filled with radiating forked 

 veins ; the other erect, and fertile. Sori open 

 transversely when ripe, and the valves are 

 concave Found in open heaths and pastures. 

 It is local, but widely distributed. 



Genus 18, Ophiogl ossum. 



Marginal-fruited ferns, having the spore- 

 cases sessile in simple spikes, terminating a 

 separate branch of the frond. Comprises 

 / r ulgatum only. 



OphlOglossum Vulgatum, (Common 

 Adder's Tongue). — It is a small stemless plant, 

 producing a few coarse roots and from which 

 one frond rises in Spring. Fronds grow from 

 6 to 10 inches in height, with a smooth round 



NATURALIST. 



succulent stipes (below), and becoming 

 divided into two branches (upper part), one 

 of which is leafy, entire, and orate-obtuse. 

 The fertile branch is erect, contracted, and 

 forming a linear spike of spore-cases. Fronds 

 appear in May. Found in damp meadows 

 and pastures, It is common and well 

 distributed. 



(the end). 



CONCHOLrOGY. 



LAND AND FRESH- WATER SHELLS 



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



Genus Valvata. 

 In this genus there are tw3 species, the 

 shells of which are very dissimilar, one being 

 glolular like a Helix, the other flat like a 

 Plan r/bis. The operculum is spiral with a 

 central nucleus. The animal has slender 

 ! tentacle?, with the eyes at the base oatheinaer 

 side ; the head is prolonged into a sort of snout, 

 the foot is divided in fr:n l into two segments, 

 and the gills or branchia j are external and 

 plume-like. The species are Pischi ills and 

 Cristata. 



Piscinalis- — This is a small shell shaped 

 like a Helix, globular, with raised spire and 

 umbdicus, and aperture nearly circular, it is 

 pale straw color, finely striated. The animal 

 is white. It dwells in gently flowing streams, 

 caaals, &; , in all parts of the country. 



Cristata. — A still smaller shell, coiled 

 into a flat disc like a PlanorUs, the spire a 

 little sunk, the whorls rounded, the aperture 

 small and round. It may be found in similar 

 situations to the last. 



FAMILY, NERITACEA. 

 Genus, Neritina. 

 In this genus we have only one species, the 

 shell is rather solid and prettily colored ; the 

 animal has long slender tentacles, at the outer 

 sides of which are the eyes raised on short 

 separate stalks. The name of the genus is 

 Flwuiatilis. 



