110 



ARTICDLATA. 



No. 452. Locusta speciosa, Miinst. 



This fossil Locust was discov- 

 ered in the Lithographic lime- 

 stone (Middle Oolite) atEichstadt, 

 Bavaria. Like the Dragon-Fly 

 above, it was doubtless blown far 

 out from the shore which border- 

 ed the marine waters of the old 

 Solenhofen Sea. The calcareous 

 mud at the bottom of this sea 

 was of the most impalpable fine- 

 ness, and enveloped closely all or- 

 ganisms which become imbedded 

 I in it, copying with beautiful ex- 

 actness their most perishable por- 



^^^^^If^^lB ^iiSilill^illll^Iiil^iilgll tions and most delicate linings. 



Size, 7x7. Price, $1.2 



CLASS III. — ANNELIDA. 



Worms lie at the lowest step of the Articulate series. They are dis- 

 tinguished by a soft, annulated body of a lengthened form, without any 

 division into cephalo-thorax and abdomen, and by the possession of red 

 blood — the only case among Invertebrates. According to Quatrefages* 

 the Annelid fauna presents no division into zoologic regions or centres of 

 creation which in other classes are so well marked out ; and moreover, 

 on granite and schistose shores, the number of species and individuals is 

 large, while on calcareous coasts it is correspondingly small. 



Worms have left traces in every deposit in the form of shelly cover- 

 ings, burrows, or imprints. Worm-holes abound in the Potsdam sand- 

 stones j they were made at tide-level, vertically, and often in pairs. The 

 most common kind is the Scolithus linearis. Hall, however, reckons this 

 a Fucoid. The Nereis, the most perfect of living Annelids, is also 

 found fossil in the Silurian, where it has left clear imprints of its cylin- 

 drical body and of the tuft-like appendages thickly distributed — a pair 

 to each segment — along its sides, and which served it both in respiration 

 and in locomotion. Serpulites abounded most in the Oolitic seas. The 

 regular Tentaculites and vesicular Cornulites of the Upper Silurian are 

 supposed by Murchison and others to be Annelids. 



