Muschelkalk, Germany.]
[Illustration: Fig. 143.--_Aspidura loricata_, a Triassic Ophiuroid.
Muschelkalk, Germany.]
The remains of _Articulate Animals_ are not very abundant in the
Trias, if we except the bivalved cases of the little Water-fleas
(_Ostracoda_), which are occasionally very plentiful. There are
also many species of the horny, concentrically-striated valves
of the _Estherioe_ (see fig. 122, b), which might easily be
taken for small Bivalve Molluscs. The "Long-tailed" Decapods
of the type of the Lobster, are not without examples but they
become much more numerous in the succeeding Jurassic period.
Remains of insects have also been discovered.
Amongst the _Mollusca_ we have to note the disappearance, amongst
the lower groups, of many characteristic Palaeozoic types. Amongst
the _Polyzoans_, the characteristic "Lace-corals," _Fenestella,
Retepora_,[22] _Synocladia, Polypora_, &c., have become apparently
extinct. The same is true of many of the ancient types of
_Brachiopods_, and conspicuously so of the great family of the
_Productidoe_, which played such an important part in the seas
of the Carboniferous and Permian periods.
[Footnote 22: The genus _Retefora_ is really a recent one,
represented by living forms; and the so-called _Reteporoe_ of the
Palaeozoic rocks should properly receive another name (_Phyllopora_),
as being of a different nature.
Pages:
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325