676 
DAVID H. TENNENT 
Two things were noted as a result of this experiment. First, 
the time of beginning of cleavage and the rate of cleavage are 
nearly constant in a given lot of eggs. Lot CF began its separa- 
tion into two cells in 39 minutes. Lot DF showed no constric- 
tion until 43 minutes after impregnation. Second, a variation; 
larvae of an auricularian type in lot AF. On the third day when 
a count of one hundred embryos was made 13 per cent were found 
to be of this type, the body elongated and with neither oral nor 
anal arms. A skeleton was present. 
Experiment 2. Five females A, B, C, D, and E were selected 
and the eggs of each divided into two portions, Ai-Ei and A2-E2, 
each portion being placed in a separate aquarium. Lots Ai-Ei 
were fertilized with sperm from male F. Lots A2-E2 were ferti- 
lized with sperm from male G. Temperature at fertilization 
27° C. During development 27°-28°. Lots AiF and A2G 
showed the same variation, a divided condition of either the 
right anal or of the left anal arm. (Type, fig. 17.) No other 
noticeable multiplicity or defect occurred. 
Experiment 3. Five females. A, B, C, D and E were selected 
and the eggs of each divided into five portions A1-A5 through 
E1-E5, and each lot placed in a separate aquarium. 
Lots Ai-Ei were fertilized with sperm from male F 
Lots A2-E2 were fertilized with sperm from male G 
Lots A3-E3 were fertilized with sperm from male H 
Lots A4-E4 were fertilized with sperm from male K 
Lots A5-E5 were fertilized with sperm from male M 
Temperature at fertilization 28°. During development 27°-28°. 
After the 3rd day all of the A series, i.e., AiF, A2G, A3H, A4K, 
A5M were characterized by the presence of a high percentage of 
larvae which under favorable conditions would have completed 
their metamorphosis. With a slight deviation either way, of a 
hundred plutei counted from each of the five lots, 21 per cent 
showed these characters . 
Series B was weak from the first. At the end of the 3d day all 
of this lot with the exception of B4M were dead. 
