42 EDWIN G. CONKLIN 
TABLE 11 
Diameters and volumes of the nuclet, 2-cell to 16-cell stages of Fulgur carica 
| | 
DIAMETER OF TOTAL VOLUME OF COEFFICIENT OF 
SNE TERA NSO OBE TEOES) NUCLEUS NUCLEI NUCLEAR GROWTH 
i ath a : M . cubic 
PACES AMS | CAD id westiererie scheiele eye 40 67,020 | 1.0 
Aceliis AWB Gu): scans 32 68,628 | 1.02 
TAS TID Ar te aan deat 32 68,628 
8 cells { 3 
ot \issid.\’.) eee 16 8,576 
77,204 1.1155 
DIASO DE: ete eee nee By 68,628 
12 cells’ a2 ye eee 16 8,576 
ar 6 IN re de oe a 16 8,576 
85,780 1.28 
| 
SASS Die eee ee: | 382 68,628 
Sa S diecaes ee ee | 16 8,576 | 
16 ll | ) | 
aia pies te oa aes | 16 8,576 
Lis has] io ka Sapeh ene re Bh | 16 8,576 
| 94,356 1.40 
theless they indicate the general rate of nuclear growth in this 
prosobranch. 
In fourteen nuclear divisions there has been an increase in 
neuclear substance of 40 per cent, or an average increase for each 
division of 2.8 per cent. The rate of nuclear growth is practically 
the same in the other species of Crepidula as in C. plana; and 
in all prosobranchs the nuclear material increases but slightly 
during the cleavage period. 
83. Nuclear growth during the cleavage of other anvmals. From 
a casual examination of the segmenting eggs of nematodes, echin- 
oderms, amphioxus and ascidians, as well as from a study of the 
figures of various authors, it is evident that the nuclear growth 
in these forms is greater during the early cleavages than in the 
gastropods. In all of these forms the germinal vesicle is relatively 
much larger and the egg and sperm nuclei much smaller than in 
the gastropods, while the decrease in nuclear size in the early 
