OF SOUTIIEFX IXDTA. 
part of the body witli the alimentary canal po.ssil)le ; they consist of two principal 
bundles attached near the oral margin and at the base of the cell. Beside that 
there are special muscles for the contraction of the moutli and of the oesophagus ; 
rotatory muscles for regulating the movements of the tentacles, &c. 
Both longitudinal and transverse muscidar striation has been observed in the 
Ciliopods. 
The centre of the nervous system is a small ganglion, or a pair of ganglia, 
situated on the dorsal side of the oesophagus, as in other ]\roltusca. From it pro- 
ceed branches to the base of the tentacles and to the other parts of the bod}^. They 
have been studied with very great detail by Hyatt in the Phylactolsemata, and 
have received different names according to the parts of the body wliich they supply. 
(Comp. Proceed. Essex Institute, vol. v, p. 104 and seq.). There are no special 
organs of sensation, Imt the soft parts of the body are sensible both to touch and 
the influence of light. The tentacles particularly appear among other parts to repre- 
sent the organ of touch. 
Proj^agation takes place either by buds or by ova. The former are of two kinds, 
external or internal. The first has as its object the enlargement of the colony. 
It begins Avith a slight protuberance of the cctocyst, filled AAuth a granidar mass, 
Avhich soon separates the endocyst, in which gradually the young Ciliopod is 
developed, resembling in form and structure the mother cell. The internal bud- 
ding consists in the formation of the so-called statoblasts, rounded or ovate, 
and more or less compressed, bodies which are formed at or near the base of the 
endocyst, and often are provided AAuth separate hook-like appendages on tbeh edges. 
Generally a number of statoblasts is found attached to the funicula in different 
stages of development. The propagation by statoblasts is of common occimcnce 
in the fresh AA’ater Ciliopods, but it has not equally satisfactorily been observed in the 
marine forms. The development of the young from the statoblast is somcAvliat 
similar to that from the ovum. Tlic animals are, as far as knoAATi, hermaphrodites, 
but the ovarium and the testicle arc attached separately to different portions of the 
endocyst. The development from the ovum begins by a separation of the yolk 
mass fronr the ectocyst, until the young Ciliopod resemble a single sac, closed on 
one end and Avidely open on the other, and surrounded Avith a row of cilia at its 
margin ; the embryo is then perfectly free, swimming about, and either this, or the 
stato-blast stage, is the only independent locomotion we know in the Ciliopod indivi- 
dual. After a time the embiyo becomes fixed to some foreign object, and then the 
usual increase of the colony by external budding goes on. In some fresh Avater forms, 
as in Cristutello, the colony retains its flexibility and the power of slightly changing 
its place, but, in by far the greater number of species, the colony is permanently fixed. 
Premising these fcAV general remarks on the organisation of the Ciliopods as 
a class, I will just allude to the principal divisions Avhich have been distinguished, 
and briefly notice the distribution in time and space ot those groups Avitli Avhich 
Avc are here more particularly concerned. 
( 37 ) 
