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Cypridina
Monopia
This sub-family consequently comprises at the présent moment in my opinion five natural
recent genera altogether, one of them consisting of two and another of five sub-genera.
Grenus Crossophorus
,, Codonocera
,, Gigantocypris
Sub-genus Doloria
,, Vargida
., Macrocypridina
„ Cypridina
,, Siphonostra
,, Monopia
,, Cyprid,inodes.
Is it possible to establish the mutual relationships of these units? Are there any
forms within this sub-family that can be indicated as being more primitive than the others?
On aecount of the great uncertainty and incompleteness that, as I have pointed out
above, distinguishes a great many of the descriptions of the forms belonging to this sub-family,
it may perhaps seem too early to attack these difficult problems alreadv. The result is destined
a priori to be both meagre and uncer tain. In spite of this I shall make an attempt in this
direction on account of the importance of the enquiries.
To obtain an answer to these questions I have undertaken as detailed a comparison
between these groups as is possible with the incomplete diagnoses at my disposai. In doing
this as great a number of characters as possible have been taken into considération. If
I were to put forward here all the results arrived at during this work it would be a very
comprehensive statement. It may, however, not be convenient to do so on account of the
great incompleteness and uncertainty of the greater part of the diagnoses in question. Onlv
the main results of this investigation will be given below.
Besides the incompleteness and uncertainty of the maj ori ty of the diagnoses of genera
and species previously given, the difficulty in deciding the classificatory value of the different
characters is an obstacle in determining the phylogenetic position of the various units. The
question continually arises : is the resemblance the result of common rnheritance or of convergence ?
According to what I myself have observed, convergence appears to be bv no means
rare within this sub-family. In any case it is quite certain that it occurs, rather good evidence
of it being found, as for instance in the furca.
The furca seems originally within this group to have been characterized by the fact
that its claws were well defined from the lamellae and decreased uniformly in length the more
proximally on the lamellae tliev were fixed. The faet that this furcal type prevails in all the
families belonging to the sub-ordo Cypridiniformes supports this assumption. Within the
sub-family Cypridininae we find a furca of this type in apparently ali species of Gigantocypris.
Codonocera, Doloria, M acrocypridina, Monopia and Cypridinodes. Within the sub-genera
Cypridina (sensu meo), Vargida and Siphonostra we find, however, other furcal types as well.
In the first of these three sub-genera the following furcal types may be distinguished:
The mutual
relation-ships of the units.
Difficulties.
Zoolog, bidrag, Uppsala. Suppl.-Bd. I.
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