488 
The Ohio Naturalist. 
[Vol. VI, No. 5, 
There is a difficulty in regard to the probable influence of the 
X' and 2x number of chromosomes in (letermining the gameto- 
])hyte and sporophyte generations, but the double or half num- 
ber of chromosomes may not be the important factor in deter- 
mining the generation. The solution of the problem must rest 
until the cytology of the tissues involved has been thoroughlv 
established. However these phenomena may be explained, they 
must be regarded as only incidental deviations which have 
arisen in plants belonging to a highly specialized group originally 
possessing a typical alternation. The presence of apogamy and 
apospory has nothing to do with the normal evolution of the 
alternation of generations in the higher plants. 
A LIST OF ISOPODA FROM THE STATE OF OHIO, PRE- 
SERVED IN THE MUSEUM OF THE CINCINNATI 
SOCIETY OF NATURAL HISTORY. 
Josu.4 Lindahl. 
This list was read at the Cleveland meeting of the Ohio Acad- 
emy, in November, 1904, but was not turned over to the Secre- 
tary for publication at the time. Now since we have such an 
exceedingly good treatment of the subject in “A Monograph on 
the Iso])ods of North America” by Harriet Richardson (Bull. 54, 
U. S. N. M.) it appears appropriate to publish the list in the 
Ohio Naturalist to encourage the search for more species in the 
State, as there surely must lie more than I have collected. 
Indiana has some species of Asellidae which are not in my list. 
Pam. Asellhiae. 
Mancasellus macrourus Garman, Hamilton Co. 
Asellus communis Say, Hamilton Co., Sandusky (E. L. Mo.seley). 
Pam. Oniscidae. 
Cylisticus convexus De Geer, Hamilton Co., Springfield (Mrs. Eva 
Engstrom), Columbus (H. Osborn). 
Porcellio laevis Latreille, Cincinnati. 
Porcellio rathkei Brandt, Hamilton ('o., Springfield, Columbus (H. 
Osborn). 
Porcellio scabtr Latreille. Hamilton Co., Sjiringfield. 
Metoponorthus pruinosus Brandt, Hamilton Co., Springfield, Colum- 
bus (H. Osborn). 
Pam. Armadillididac . 
Armadillidium vulgare (Latreille), Hamilton Co., Springfield. 
The collection of Isopoda in the museum, comprising, at 
jiresent, 19 genera, 30 species, has lately been revised by Dr. 
Harriet Richardson, the eminent Carcinologist of the U. S. 
National Museum in Washington. 
Cincinnati. 
