FRULLANIA. 



[ 273 ] 



FRUSTULIA. 



the toes vidth silk or cotton threads to httle 

 tacks or nails driven into the wooden plate. 

 Metal " frog- plates" are sold for the piu'- 

 pose. Section of the kidney of the frog, 

 made with a Valentin's knife, will show the 

 ciliated epithelium of the necks of the uri- 

 nary tubules. The circulation of the blood 

 in the lungs and the mesentery may be ex- 

 amined, but the animal should be rendered 

 insensible by chloroform before the experi- 

 ment. 



The ova of the frog (frogs' spawn) have 

 formed the subject of some of our most in- 

 teresting experiments on impregnation and 

 development. The larvae (tadpoles) exhibit 

 well the circulation in the gills, tail, and 

 more transparent parts, and afford easily ob- 

 tained materials for the study of the develop- 

 ment of the tissues. The chorda dorsalis is 

 well seen in a young tadpole. The frog and 

 tadpole are however inferior in most respects 

 to the Triton and its larva for exhibiting 

 these phsenomena. 



The injected organs of the frog afford 

 most interesting and beautiful preparations ; 

 especially the lungs, kidneys, skin, tongue, 

 and web of the foot. The injection should 

 be thrown in at the heart, and the slightest 

 possible force used. 



The simplest method of killing a frog 

 without injmy, is to immerse and retain it in 

 warm water. The primary effect of this pro- 

 cess is, however, only that of producing 

 asphyxia ; so that if it be removed from the 

 water and exposed to the air too soon after 

 immersion, even, as in injection, after the 

 pipe has been fixed in the heart, it will re- 

 vive ; and probably when the operator has 

 returned from stirring the injection, the frog 

 will have vanished, and may perhaps be 

 found jumping on the floor. Such unneces- 

 sary cruelty may easily be avoided by attend- 

 ing to the above remark. 



FRULLANIA, Raddi.— A genus of Jun- 

 germannieae (Hepaticaceae), containing three 

 British species, the Jungermannia Hutchin- 

 sice, dilatata, and Tamarisci of Hooker's 

 British Flora. F. dilatata is very common, 

 creeping on the bark of trees, its dark brown, 

 dry foliage appearing like minute spreading 

 blotches ; the almost sessile capsules are 

 somewhat inconspicuous, but are distin- 

 guished by their whitish colour. The valves 

 of the capsule and the elaters afford beautiful 

 microscopic objects, illustrative of the spiral 

 structures in cells. F. Tamarisci (fig. 255) 

 has longer and more regularly pinnate stems, 

 forming large lax tufts on the ground and 



low bushes, chiefly in sub-Alpine coun- 

 tries. 



Fig. 255. 



Frullania Tamarisci. 



Portion of a stem with branches bearing the perichsetes 

 from which the sporanges emerge. 



Magn. 5 diams. 



BiBL. Hook. Brit. Jungermannia, pis. 1, 

 5, 6, Brit. Flora, ii. pt. 1. p. 128 ; Endlicher, 

 Gen. Plant. Suppl. i. No. 472-10. 



FRUSTULIA, Ag.— A genus of Diato- 

 maceae. 



Char. Frustules resembling those of Navi- 

 ciila, irregularly scattered through an amor- 

 phous gelatinous mass. Aquatic. 



F. salina, Ehr. Frustules in front view 

 very narrowly linear, rounded at the ends ; 

 valves suddenly acute at the ends, transverse 

 striae evident; gelatinous envelope continu- 

 ous; length of frustules 1-2200 to 1-864". 

 Found in a saline spring. 



This organism is of particular interest, 

 as having formed the subject of Schmidt's 

 ultimate analysis, in which he determined 

 the presence of cellulose. (Diatomace^, 

 p. 200.) 



F. saxonica, Rab.(P1.13. fig.l7). Frustules 

 in front view linear, rounded at the ends ; 

 valves elliptical, somewhat acute. 



Forms dirty olive-brown, gelatinous, tre- 

 mulous masses, contained in small pits in 

 rocks. 



F. memhranacea, nobis (PL 41. fig. 6). 

 Frustules in front view linear, very slightly 

 narrowed towards the ends ; valves lanceo- 

 late, constricted near the obtuse ends; length 

 of frustules 1-1250". 



This was found abundantly forming a thin 

 stratum or film upon the sides of a glass jar 

 containing water-plants. 



Rabenhorst describes four other aquatic 

 species. 



BiBL. Ehrenb. hifus. p. 232; Kiitzing, 



T 



