120 REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 



Filameut extrusion : Most certainly produced in the fresh state by 

 strong sulphuric acid, iodine water, glycerin, nitric, hydrochloric, 

 acetic, formic acids, allialine hydrates, boiling water, ether, etc., espe- 

 cially the first two. In alcoholic specimens, also, occasional spores 

 extrude their filaments under the action of sulphuric acid or iodine. 



VIII.— DEFINITIONS. 



Anterior (and posterior) : There can be no question that the longitudi- 

 nal diameter is the anteroposterior axis of the body. The discrimina- 

 tion of anterior from posterior is, however, in the absence of cephalization, 

 impossible. I have followed custom iu calling the sharper, capsular end 

 "anterior," and the opposite rounded end "posterior." 



Capsules: The pyriform, hollow, filament-containing bodies charac- 

 teristic of the myxosporidian spore ("twinned vesicles" of Balbiani; 

 "polar capsules" of Biitschli). "Capsule" is preferred to " vesicle" on 

 account of greater definiteness, and to "polar capsule," as the situation 

 imi)lied by the latter is not constant. 



Cornua: The pointed anteriorly projecting extremities of the sporo- 

 plasm. They are infero-, and superolateral, and infero-, and supero- 

 mediau. (See also Surface, superior, p. 122.) 



Diameter, longitudinal: The line formed by the intersection of the 

 longitudinal and vertical planes. 



Diameter, transverse: The line formed by the intersectioij of the 

 transverse and longitudinal jilanes. 



Diameter, vertical: The line formed by the intersection of the verti- 

 cal and transverse planes. 



Ducts: The ducts into which the capsule is drawn out anteriorly and 

 which serve for the exit of the filaments. 



Ends (of the spore): The median (anterior and posterior) extremities 

 in contradistinction to the wings. 



Filaments: The filaments which lie coiled within the capsules. The 

 "capsular filaments," "spiral filaments," and " coiled filaments" of the 

 authors. Isfotto be confounded with the ribbonettes. 



Host: In the usual sense; see also Seat. 



Myxoplasm: The protoplasm of the myxosporidium. 



Myxosporidium : The amwboid adult stage; Muttcrhlase, Leydig. 



Pansporoblast: see Sporohlast. 



Pericystic space: The space apparently empty (presumably fluid- 

 filled) surrounding the capsules. 



Plane, longitudinal:^ Horizontal and percapsular, passing through 

 both capsules and the sporoplasm, and dividing the spore into a supe- 

 rior and an inferior portion. 



' For brevity aud clearness these planes are defined as if rectangularly arranged 

 about the center of the Myxoholus spore, the latter being supposed to be viewed " ou 

 the flat." 



