766 THE AMERICAN NATURALIST. [Vor. XXXIV. 
Relation between Nervous and Glandular Tissue in Ascidians. 
— ]t is now fully established that the brain and neural gland in the 
ascidian embryo develop from a common Anlage. Professor M. M. 
Metcalf (Biol. Buil., Vol. I, No. 1) has studied the relation of the 
nerve and duct which spring from the brain and gland, respectively, 
and run along the median line on the partition wall between the : 
pharynx and cloaca, and finds a closeness of relations there between 
the two tissues that is quite as remarkable as is the fact of their 
common origin. 
In Amaroncium constellatum, for example, a rudimentary duct starts 
out from the gland, but soon loses its lumen and becomes so inti- 
mately united with a strand of cells from the brain that it is impos- 
sible to tell whether the common mass should be regarded as coming 
from brain or gland. W. E. RITTER. 
The Life Cycle of Adelea Ovata, a coccidium parasitic in the 
digestive epithelium of Lithobius, has been described by Siedlecki." 
When the sporocysts, which are resistant stages, are taken into the 
intestine of the host, the two sporozoites are liberated from the cyst 
and enter the epithelium, where, by a process of endogenous gtnera- 
tion, they give rise to two sexually different stages, the microgameto- 
cytes and the macrogametes. These pass into the lumen of the 
intestine, where a smaller microgametocyte attaches itself to a 
larger macrogamete and undergoes two divisions, producing four 
microgametes. These two divisions differ in character, the first 
being a regular division resulting only in a quantitative reduction 
of the chromatin, while the second is irregular and apparently 
reduces the number of chromosomes. The nucleus of the macro- 
gamete also rejects a portion of its chromatin. A single micro- 
gamete then unites with the macrogamete, and divisions follow 
which result in the formation of the resistant d 
C 
Notes. — In the Prague Sitzungsberichte Dr. Mrazek describes 
the destruction of cysts of the sporozoan Glugea in the spinal cord 
of Lophius by the phagocytes of the host which press through the 
walls of the cyst and devour the spores. 
The limnetic Peridinidæ of Norway are discussed by Huitfeldt- 
Kaas in the Christiania Skrifter. Five species are reported, of 
1 Siedlecki, M. Étude cytologique et cycle évolutif de Adelea ovata Schneider, 
Ann. de l Inst. Pasteur (1899), pp. 169-192, Pls. I-III. 
