Conard: Structure of Simblum Sphaerocephalum 267 
intercalated beneath the head. Meanwhile the plates elongate pari 
passu, resulting in the condition shown in text fig. 3. If this be 
true, as seems almost certain, the stalk would seem to be an organ 
of much more recent origin than the head of the receptaculum. 
It may be regarded as an extreme development of the basal ring 
of the receptaculum of Clathrus (text figs, i, 2, a). This agrees 
with the generally accepted view that Clathrus is one of the most 
primitive of the Clathraceae. 
Fischer (1890, p. ii) supposes that the difference between the 
early stages of development of Simblum and Clathrus would be 
that in the former the branches of the central strand come off 
Fig. I. — I. Vertical section of very young egg of Clathrus cancellatus, from 
Fischer 1890, pi. i, f. 3. — 2. The same, mature egg; 1 . c. f. 6. — 3. Diagram of 
vertical section of mature egg of Simblum sphaerocephahun, a lowest ring of 
receptaculum ; other letters as in plate. 
higher up than in the latter (“ Der Unterschied der ersten Frucht- 
korperanlage von Simblum gegeniiber derjenigen von Clathrus 
besteht also darin, dass vom Centralstrang hier erst weiter oben 
als dort Zweige abgehen”). But if the central strand branches 
higher up, there should be no volva- jelly around the stalk — unless 
the branches force themselves down between the layers of the 
peridium and the plates, parallel to the stalk. It seems much 
