Phylum Protoplasta [173 



material, a millimeter or more in height, and ascend upon it. Each separate body of 

 protoplasm secretes an external wall and begins to undergo cleavage within it. Har- 

 per (1900) described the details of the process. All authorities agree that the nuclei 

 undergo a flare of divisions at this time (Strasburger, 1884; Harper, 1900, 1914; 

 Bisby, 1914). It is almost certain that there are two flares of division, constituting the 

 meiotic process, but few authorities have positively affirmed this (Schiinemann, 

 1930)1. Cleavage is carried to the point of producing uninucleate protoplasts. While 

 this is taking place, many species secrete a network of hollow tubes or a system of 

 hollow fibers, called the capillitium, by deposition of lifeless material outside the 

 cell membranes. In species which produce a true capillitium, all of the uninucleate 

 protoplasts secrete walls and become spores. Strasburger found the capillitium and 

 the walls of the spores to consist of impure cellulose; others have found no cellulose. 

 In many species which do not produce a true capillitium, an analogous structure 

 called a pseudocapillitium, consisting of solid bodies of various forms, is modelled 

 from a part of the nucleate protoplasm which is deprived of its reproductive function 

 and killed. In many species, much calcium carbonate is deposited in the wall, or 

 both in the wall and in the capillitium or pseudocapillitium. 



A small separate fruit is called a sporangium. A fruit of the form of a large mass, 

 or of many sporangia not completely separate, is an aethalium. The spores are re- 

 leased by collapse of the outer wall. 



These organisms are of no known economic importance. There are some forty 

 genera, between four and five hundred species. As Lister remarked, the same species 

 occur everywhere: collections from Colombia (Martin, 1938) and from Mount 

 Shasta (Cooke, 1949) consist entirely of familiar species. 



Rostafinski (1873) arranged the genera in two cohorts, seven orders, and nineteen 

 tribes, the last with names in -aceae. His subsequent monograph of the group ( 1875) 

 was regrettably published in a barbarous language, and is for nomenclatural purposes 

 a nullity. All later systems are based on Rostafinski's original system. The group being 

 essentially uniform, it is properly treated as a single order. 



Definite families were first established by Lankester, mostly under names which 

 Rostafinski had applied to tribes. Berlese (in Saccardo, 1888) provided a complete 

 set of names in -aceae, valid under botanical rules; Poche provided a complete set in 

 -idae, valid under zoological rules. Authorities have differed moderately as to the 

 list of families; here, somewhat arbitrarily, fourteen are maintained. 

 1. Capillitium none (order Cribrariales Mac- 

 bride). 



2. Producing separate sporangia, pseudo- 

 capillitium none. 



3. Sporangia shattering irregularly or 

 opening through a terminal oper- 

 culum Family 1 . Liceacea. 



3. Sporangia opening through numer- 

 ous pores, the walls becoming sieve- 

 like Family 2. Cribrariacea. 



2. Fruits aethalioid, pseudocapillitium 

 present. 



iWhile the present work was in proof, Wilson and Ross (1955) established the point 

 that meiosis occurs immediately before the formation of spores. 



