219 
1913. Muller, C. — Einige Falle von Doppelbildung und Concrescenz bel 
Hydroiden. — Zoolog, Anzeiger. Bd. 42. pp. 104—112. 
1913. W i 11, L. — Der Einfluss des Hungers auf die Hydroiden und seine 
kausale Beziehung zum Polymorphismus. — Sitzungsber. u. 
Abhandl. der Naturforsch. Gesellsch. zu Rostock. Bd. V. 
pp. 33—56. 1 Taf. 
Explanation of Plate III. 
Fig. 1. Branch of Laomedea geniculata with three frustules in various stages 
of development. — In a the coenosarc nearly filis out the perisarc. 
— In ^ the thread is somewhat longer, and the middle part of the 
coenosarc is thin and not connected with the perisarc. — In c the 
distal part of the coenosarc is separated from the proximal part; the 
frustule has still a thin proximal part, a tail. x. 20. 
Fig. 2. A frustule of L. geniculata just before the moment of deliberation, 
rounded in both ends, but still resting within the unbroken tube 
of perisarc. x 20. 
Fig. 3. A frustule of Laomedea longissima, still connected with the coenosarc 
of the branch, x 48. 
Fig. 4. A frustule of 5. longissima with a young hydranth. Showing the 
vertical wall separating the “chamber“ from the open chitinous tube. 
X 48. 
Fig. 5. Another frustule of the same species. — The coenosarc of the cham- 
ber has partly been drawn up into the pedicel of the developing 
hydranth. x 48. 
Fig. 6. A primary stolon of a frustule of L. longissima with the marks of 
two pedicels of hydranths (cut off) and with a secondary lateral 
stolon. X 48. 
