LAGENIDA. 37 
The chief variations from this central type depend upon alterations in the nature of 
surface-ornamentation, or the shape, length, and direction of the neck. We are fully 
convinced that there is no true specific division determinable from these characters, either 
among the costate group above indicated, or even in the much wider range of Lagene 
in general. ‘The division of the genus into Ectosolenian (Zagena) and Entosolenian 
(Entosolnia) groups, adopted by Professor Williamson, in his Memoir on the Zagene, 
and in his Monograph, whilst it might afford us some general assistance im classifying a 
bulky list of varieties, seems only to lead into greater difficulties, for we find that the 
principal forms may be traced in series from the pear-shaped body, with the long, thick- 
lipped neck, through every gradation of shortening, and eventually of intussusception. 
But if the distinctions founded on contour be thus open to objection, still less dependence 
is to be placed on the shape of the aperture, for systematic purposes. There can be little 
doubt that the typical form of the aperture, if we may judge from the finest and most 
fully developed specimens, is very similar to that of the Polymorphine and Nodosarine, a 
circular orifice surrounded by radiating lines. The radiation is only to be observed in 
exceptional specimens; but the majority of the Zayene preserve the circular form of 
orifice. In the feebler varieties, especially those which have no neck, there is a tendency 
towards an oval form of orifice, and in the flattened specimens grouped as LZ. marginata 
the typical round mouth is represented by a mere slit. Professor Reuss has divided his 
family Lagenida into two genera, Lagena and Fissurina, on these peculiarities. It has 
been reserved for Professor Seguenza to carry subdivision to an extreme. He recognises 
no less than eight “ genera” of Lagenida, namely, Ovulina (shell oval, aperture circular), 
Pihialina (shell oval, aperture at the top of an elongated tube), Amphorina (shell fusiform, 
aperture circular), Zetragonulina (shell square and tubulated, aperture circular), Fisswrina 
(shell compressed and equilateral, aperture in the form of a slit), Amygdalina (shell com- 
pressed and inequilateral, aperture slit-like), Zrigonulina (shell triangular, aperture slit- 
like), and, lastly, Od/quina (shell twisted, aperture circular). 
We need not say that with such a generic subdivision we have no agreement; and 
still less, if it were possible, with his list of new species—an example of hair-splitting to 
which we know of no parallel in systematic zoology. Of the 102 ‘“‘new species” of Lagene 
described in his memoir, there may, perhaps, be four or five undescribed forms worthy of 
subvarietal names; the rest are ordinary specimens of well-known forms, long since 
described. If the system pursued by the Italian professor were to be followed, it would 
soon become necessary to describe and name every individual specimen. 
As we have before stated, the situation of the general aperture in relation to the body 
of the shell is exceedingly open to variation, even in groups of specimens identical in their 
other characters. We find in rare examples, under similar limitations, another complicity 
in the classification, arising from the occurrence of an orifice at each end of the shell. This 
peculiar development may be traced through the “ caudate” varieties of the various forms ; 
and, as all the feeble Zagene, especially clear-shelled and slightly striated individuals, have 
