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Division o/
f am ili/.
1,0 mm. long. The mature specimens were assumée! to belong to ,,Stage I“, the three larvae
to the last larval stage, ,,Stage III“. The reason why the mature specimens were assumed to
belong to „Stage I“ was obviously the relatively great difference with regard to the length of
the shells between these specimens and „Stage III“; these two stages were really presumably
separated by an intermediate stage. The question then becomes: did the three larvae really
belong to the last larval stage? Unfortunately the statements given are too incomplete for me
to venture to say anything cpiite definite in this matter. It seems to me, however, from pl. XIX,
fig. 77, very probable that these three specimens belonged to the next to the last larval stage.
If this is the case, then the reason for assuming a mature stage between the stages found by
G. H. FOWLER also disappears. On the other hånd G. H. Fowler found in this material two
stages of mature females, „Stage I“ being represented by seventeen specimens, „Stage II“
by only three. Were both these stages mature? For the same reasons as in the case of the males
it is very difficult for me to make any statement on this point, but it seems to me practically
quite certain that the three specimens of „Stage II“ were not mature; pi. XIX, fig. 80 definitely
shows this. They were probably larvae in the last stage. If this is the case, there was in this
sex too only one mature stage.
What has been said above will be sufficient to show clearly how uncertain is the basis
on which G. H. FOWLER has constructed his important hypothesis.
As is seen above, p. 564, this group was divided by G. W. MÜLLER, 1906 a, into two
subfamilies: Thaumatocyprinae and Conchoecinae. The same classification is also used in the
present treatise. Of these two sub-families Thaumatocyprinae, which is so interesting from
a systematic point of view, was unfortunately, however, quite unrepresented in the collections
investigated by me.
Sub-Family Conchoecinae.
Slib-Fam. Conchoecinae, G. W. MULLER, 1906 a, p. 43.
Description: — Shell: — Thisisdimorphous, but in a number of cases only rather slightly
so. —- The rostral incisur is shallow in all species, but it never seems to be quite absent. An apparent
deepening of the incisur occurs, however, in all the forms so far known. This deepening has arisen
because the outer lamella of the shell curved out like a pocket just above the incisur, forming a
rostrum which is in most cases rather extensive (this rostrum is thus not homologous with the part
with the same mime in the Cypridiniformes); the original anterior margin of the shell continues
(as G. W. Müller pointed out as early as 1894, p. 101) in the shape of a more or less S-shaped
curved line („Buchtlinie“, according to C. C’LALS’s terminology) proximally on the inside, or
perhaps more correctly speaking, on the ventral side of the rostrum. The rostral incisur is always
situateil above half the height of the shell, in most cases quite near its dorsal margin
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