REPORT OR THE EORAMIHIEERA. 
443 
In the scheme proposed by Reuss the division is founded upon the character of the 
external orifice, the species having a simple rounded opening being assigned to Lagena, 
whilst those in which the aperture takes the shape of an elongated slit constitute a separate 
genus, Fissurina. From the narrow standpoint of a local fauna, where the number of 
anomalous examples appears relatively small, something may be said in favour of either 
of these methods of classification ; but they fail equally to be of service, and are on the 
other hand a source of additional complication, if any attempt be made to apply them to 
large collections or to specimens gathered from wider areas. 
There are no doubt some forms of Lagena wdiich are only known in the entosolenian 
condition, but in a majority of cases the same variety furnishes both ecto- and ento- 
solenian specimens. Moebius (Foram. von Mauritius, p. 67) speaks of the entosolenian 
forms as representing a higher phase of organisation than the ectosolenian, on account of 
the internal tube ; but it may be pointed out that this peculiar feature is not confined 
to the Lagena, but is occasionally encountered in allied genera, notably in Nodosaria and 
Polymorphina ; and that it is amongst the poorly-developed modifications of the respec- 
tive types, such as Nodosaria calomorpha and Polymorphina angusta and Polymorphina 
lanceolata that the entosolenian condition is most frequently observed. 
Again the slit-like orifice, the essential character of Reuss’s Fissurina , though a 
common peculiarity of the compressed varieties, is often replaced by a rounded opening 
which may or may not be situated at the middle of a long depression. But it is needless 
to pursue this subject ; enough has been stated already to make it clear that the 
characters of the aperture are altogether too inconstant to be employed even by way of 
specific distinction. 
The sequence of forms throughout the genus is in fact too close and continuous and 
too much complicated by the overlapping of collateral varieties, to be capable of consistent 
or satisfactory arrangement of any sort. Parker and Jones treat all the known forms of 
Lagena as varieties and sub-varieties of a single species ; and from a strictly biological 
standpoint, this perhaps most nearly represents their true relationship. It is possible, 
however, to divide the generic series into sections, grouped round a few sub-typical forms, 
each section embracing a number of easily distinguished subordinate varieties, and many 
of these varieties in their turn including several minor modifications. An attempt has 
been made to indicate a graduated relationship of this sort in the annexed Synopsis, 
and though imperfect and lacking precision, the result may answer the purpose of 
a classification in the absence of anything better. 
