STOMATA. 



[ 743 ] 



leaves they occur only upon the upper face. 

 The larger kinds are moro scattered on 

 a given surface ; the smaller occur closer 

 together: this depends, of course, on the 

 general character of the epidermal and sub- 

 jacent tissue. The numbers have been 

 estimated upon the surfaces of many leaves, 

 of which a few examples may be given : 

 thus a square inch contains, on the 



Upper surface. Lower surface. 



Carnation 38,500 .... 38,500 



Garden Flag .... 11,572 .... 11,572 



House-leek .... 10,710 .... 6,000 



Tradcacantia 2,000 2,000 



Mistletoe 200 .... 200 



Holly .... 63,600 



Lilac ....160,000 



Vine .... 13,600 



Laurestinus 90,000 



BIBL. General Works on Struct. Botany ; 

 Mirbel, Mem. Ac. Roy. France, xii. ; Gas- 

 parini, Nuove ric. 8. strutt. d. Cistomi, 1844 ; 

 Garreau, Ann. Sc. Nat. 4. i. 213 ; Hooker, 

 Flora Antarct. \. 291 ; Biscoe, Mn. Mic. Jn. 

 viii. 31. ; Hohnfeldt, Bot. CentralU. 1880, i., 

 Jn. Mic. Soc. 1881, i. 71 (underground) ; 

 Prantl, Flora, 1872 ; Stein, Bot. 103. 



STOMATA or STIGMATA of Animals. 

 These are minute rounded spaces, left be- 

 tween the epithelial cells of the capillary 

 blood-vessels, lymphatics, and of the serous 

 membranes. Great importance has been 

 attributed to them, as allowing the escape 

 of the corpuscles and liquid into the sur- 

 rounding tissues. This may occur when the 

 vessels are congested and distended; but 

 not in the normal state, for the finest injec- 

 tions do not escape through them. They are 

 best seen in silver-stained preparations. 

 (Frey, Hist, and the Bibl.) 



STOMATOP'ORA=ALECTO. 



STONES OF FRUITS, such as cherries, 

 plums, &c., afford excellent materials for 

 sections, showing extreme development of 

 the woody SECONDARY DEPOSITS of vege- 

 table cells. 



STORTHOSPH^E'RA, Schulze. A glo- 

 bular Arenaceous Foraminifer with a short 

 blunt spike. German Ocean. (F. E. Schulze, 

 Commiss. wiss. Un.deutsch. ^f<?ere,1875,113.) 



STRIA'RIA, Grev. A genus of Dictyo- 

 siphonacese (Fucoid Algae), nearly related to 

 Punctariaceae, having a branched, filiform 

 pale olive, tubular frond, arising from a 

 shield-shaped naked disk. The walls of the 

 tube are membranous, and the cavity with- 

 out septa. S. attenuata (fig. 707) grows from 



STRIATELLA. 

 Fig. 707. 



Striaria atfcenuata. 

 Fig. 707. Part of a frond. One-third of the nat. siz. 



Fig. 708. 



Fig. 709. 



Striaria attenuata. 



Fig. 708. A fragment with sori. Magnified 5 diams. 

 Fig. 709. Section of a fertile branch, with sori. Mag- 

 nified 25 diameters. 



3 to ] 2" high. The branches are attenuated 

 towards each end, and marked with rings 

 consisting of clusters of simple sporanges 

 (spores) (fig. 708), sometimes accompanied 

 by filaments (fig. 709). 



BIBL. Harv. Mar. Alg. 41 ; Grev. Alg. 54. 



STRIATEL'LA, Ag. A genus of Dia- 

 tomaceae. 



Char. Frustules with a stipes attached to 

 one angle, depressed, tabulate ; with longi- 

 tudinal uninterrupted vittae, apparently 

 thickened at each end. Marine. 



The vittae appear as dark lines j no trans- 

 verse striae are visible under ordinary illumi- 

 nation. 



8. unipunctata (PI. 17. fig. 20), Frustules 

 in front view quadrangular, often broader 

 than long, lateral margins subulate ; valves 

 narrowly lanceolate j stalk elongate, simple, 

 filiform and thickish. Length of frustules 

 1-450 to 1-280". 



