243 
In the largest specimen from Slipper Island there were also larger 
opaque nematocysts sometimes irregularly curved, and 77—84 x 
about 5 // in size. They are probably development stages of the 
large typical nematocysts. The size of the nematocysts in the 
acontia is shown in the following table. (Specimens 1—3 from Slip¬ 
per Island, 4—5 from Kaipara. The specimens 4—5 were larger 
than spec. 1). 
Specimens 1) length 1,5, breadth 0,6 —0,8cm: 58—70 X 5—6 
Specimens 2) length 0,7, breadth 0,7 cm: 46 — 55 x 5. 
Specimens 3) length 0,7, breadth 0,5 cm: 48 — 55 x 5. 
14—17 X about 1,5 17—19 x 2,6—3 [i. 
14 X about 1,5 17—19 x 2 , 5 —almost 3. 
13—14 X about 1,5 17 x 2 , 5 . 
Sp. 4) 55—70 X about 6, 14—16 x about 1 , 5 , 17X2,5—almost 3. 
Sp. 5) 49—65 X about 6, 13—15 x about 1,5. 
Remarks. It is possible that this species is identical with 
Metridium canum Stuckey 1914 p. 134 from the Kermadec Islands, 
but the description of this species given by Stuckey is so im- 
perfect and short, that it is impossible to decide its place. Among 
other things Stuckey does not mention any collar. 
Diadumene minima (Stephs.) 
Aiptasia minima n. sp. Stephenson 1918, p. 49, PI. 1 flgs. 2, 3, PI 6 fig. 1. 
Aiptasiomorpha minima (Steph.) 1920, p. 531. 
Di agn osi s. Pedal disc well developed. Column smooth with 
probably few cinclides (arrangement?). Sphincter absent. Tentacles 
conical, smooth to about 70 (or more?) of ordinary length, the inner 
at least twice as long as the outer. Longitudinal muscles of the ten¬ 
tacles weak, ectodermal. 1 or 2 siphonoglyphes. Perfect pairs of me- 
senteries 6 or some more, 1 or 2 pairs of directives. The first and 
second cycles of mesenteries with pennons. Pennons diffuse with 
rather few but ramificated folds situated in the inner part of the 
mesenteries, in the directives higher and more concentrated. Parieto- 
basilar and basilar muscles weak. The first and second cycles of 
mesenteries fertile (teste Stephenson) and with filaments. Repro- 
duction also by longitudinal fission. Nematocysts of the column partly 
12-14X1,5 —almost 2/f, partly 12—14X2,5 (3)//, the latter broader 
in the basal end, those of the tentacles partly 17—22 x (2) 2,5 {.v 
16* 
