84 REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 



anteriorly into a duct which pierces the shell near its anterior extrem- 

 ity, atrordiii<>- exit for the tihiment. Wall usually taking- (sometimes 

 retaining, sometimes yielding- up upon washing out) stains, especially 

 the nuclear. Th61ohan ^ considers the substance composing the capsu- 

 lar wall identical with that forming the shell, as both stain in the same 

 way Avitli safranin. From this view 1 must dissent, as in my experience 

 not only the optical character, but also all the prominent staining re- 

 a<;tions, ditfer. In ])articular the capsules are nitijonitly opaque^ the 

 lilaments never being visible through them, even in glycerin, while 

 the shell is transparent in the highest possible degree. Further, in 

 Miixobolns macrunis (other species were not tried) bismarck brown and 

 fuchsin each stain the capsule without even tinting the shell. 



Two reagents render the capsular wall transparent, thus i)ermitting 

 the filament to be seen coiled in situ. Tlie first is iodine water (solu- 

 tion with potassium iodide). This reagent also causes extrusion of the 

 filaments, sometimes even in alcoholic specimens (i)p. 85, 120). The 

 second is strong ammonia water. I have never seen it i)roduce extru- 

 sion of the filament. 



Biitschli^ and IJalbiani'' have observed that when the filament 

 is extruded tliere is (" as in the thread cells proper", Biitschli) a very 

 marked diminution in the volume of the capsule, from which Biitschli 

 infers that such extrusion is produced by the pressure of the stretched 

 elastic capsular wall. 



This may be the cause of filament-extrusion, but might it not equally 

 well be interpreted as the result of such extrusion or, more properly, 

 as a co-result Avith the latter of a general increase of intrasporal pres- 

 sure? However this may be, it seems very probable that the filament- 

 extrusion which takes jdace under the influence of such energetic dehy- 

 drants as sulphuric acid, glycerin, etc, is merely a phj^sical effect, 

 the result of the intense intrasporal eudosmotic pressure. Thus in 

 several species (among others, Myxoholn.s transovalis) sulphuric acid 

 produces a pronounced swelling of the spore, extrusion (even in alco- 

 holic specimens) of the filaments, and finally the expulsion of the cap- 

 sules bodily, under an evidently great i)ressure. It can not, however, 

 be denied that the action of iodine water is not thus ex])licable. 



Filament. — Exceedingly tenuous, attached at its proximal extremity 

 to the capsular wall, free at its distal extremity; usually coiled into a 

 spiral; in this condition entirely inclosed within the capsule cavity. 

 Ca])able of uncoiling and of extrusion {via the capsular duct) as a semi- 

 uncoiled or a fully uncoiled (nearly or quite straight) thread whose 

 length may be many times that of the spore. That the semiuncoiled 

 condition is merely an intermediate stage between the fully coiled and 

 the fully uncoiled condition, and is not a specific character, is shown 



■ » 



1 Anual. de Microgr., 1890, ii, p. 207. 



sZtschr. f. wiss. Zool., 1881, xxxv, )>. 036. 



» Journ. de Microgr., 1883, vii, p. 204. 



