160 
Rev. T. Hincks on the 
grouping of the cells; and were this course adopted in such a 
protean class as the Polyzoa, we should have an indefinite 
multiplication of genera (see D’Orbigny’s system of classi¬ 
fication). The essential structure of the individual cell must 
certainly be accounted the most important point, both in itself 
and as a clue to relationship; and by giving the mere grouping 
a coordinate place beside it we should run the risk, it seems to 
me, of diverting attention from those natural affinities which 
it is the great object of all our classification, as far as possible, 
to indicate. 
Unless we are content with the old (and certainly very 
simple) method of lumping all erect forms together, without 
anv reference whatever to the cell, we have only a choice 
between these two courses—to found genera for the variations 
of growth as well as for the more important modifications of cell 
in each family, or to make the zooecium the basis of the genus 
and treat the ordinary variations of habit subsectionally. I 
was at one time inclined to the former method * ; but further 
experience of the practical work of classifying the Polyzoa 
has brought me, to a much greater extent, into sympathy 
with Prof. Smitt’s views. In a case like the present the true 
end of classification, the display of natural relationship, will, 
I think, be best attained by throwing the species with similar 
cells into one genus, and marking by distinct headings the 
varieties of growth. 
It may be noted here that no recent systematist, if we 
except ITOrbigny, has proposed to separate the crustaceous 
Celleporce from those which are erect and ramose; yet the 
latter are as definite in their branching and the structure of 
their stems as the Escharce. And, to take an analogous case in 
another section of the Polyzoa, by universal consent the 
incrusting and the up-growing ramified Alcyonidia are grouped 
in one genus. 
Smittia, nov. gen. 
(==EschareUa , Smitt, not of D’Orbigny.) 
Zooecia with the primary orifice suborbicular, the lower 
margin entire and dentate ; peristome elevated and forming a 
secondary orifice, which is channelled in front; generally an 
avicularium below the sinus. The zoarium in British species 
is either incrusting or rises into foliaceous expansions, with 
the cells in a single or double layer. 
For this group Smitt employs the name Escharella ; and 
* Vide a paper by the author in the ‘ Annals ’ for December, 1877, 
p. 528. 
