JENNINGS: DEVELOPMENT OF ASPLANCHNA HERRIOKII 117 
EXPLANATION OF PLATES. 
All the figures represent preparations of the eggs of Asplanchna Herrickii de 
Guerne, except Figure 29, Plate 4, which represents the egg of Asplanchna prio- 
donta Gosse. All were drawn, with the aid of the Abbe camera lucida, to a mag- 
nifieation of 525 diameters. 
The four blastomeres of the four-cell stage are distinguished by different colors, 
and the same color is retained throughout for all the cells (constituting a “ quad- 
rant”) derived from each of the four blastomeres thus distinguished, The quad- 
rant A is blue; B, orange; C, yellow; and D, red. 
The promihent granulations in the ventral portion of quadrant D are figured ; 
but all other granulations are omitted, except in the case of Figure 7, where the 
general granulation is also represented, though somewhat diagrammatically. 
For an explanation of the system of nomenclature used in lettering the cells see 
page 16. In somecases for want of room the letters have been omitted, the expo- 
nents only being expressed. In such cases the color indicates to which quadrant 
the cell belongs. 
In all the figures where it is possible, the animal pole of the egg is above, the 
ventral pole below. In views of the dorsal or ventral poles of the egg, the anterior 
end is above. Unless otherwise stated, figures represent surface views of more or 
less transparent eggs; these are shaded, whereas seetions — optical or aetual — are 
not shaded. 
ABBREVIATIONS. 
„%%% Blastopore. cl. pol. Polar cell. pol. anm, Animal pole. 
