Mr. W. H. Baily on a new Pentacrinite. 25 



ordinarily living in the open fields, should find its way to such 

 a depth beneath the surface of the ground, and multiply to such 

 an extent as to be able to construct, by the united labours of hun- 

 dreds, immense sheets of web, stretching through all the deserted 

 subterranean galleries. It seems that this little creature, at the 

 same time that it shifted its abode, must also have acquired new 

 instincts, becoming social and gregarious in its habits, and thus 

 departing from the manners of most of the spider tribe, which 

 are usually solitary, except when quite young. It may be said 

 that numerous and large spiders' webs are often met with in 

 other dark underground places besides coal-pits (as cellars, caves, 

 &c.) ; but these are always constructed by larger species, each 

 individual living separately, and having its own web ; the spiders 

 forming them may also mostly be referred to the genus Tege- 

 naria, to which our common house-spider belongs. 

 Bradford, May 30, 1860. 



VI. — Description of a new Pentacrinite from the Kimmeridge 

 Clay of Weymouth, Dorsetshire. By William H. Baily, 

 F.G.S. &c* 



[With a Plate.] 



The beautiful fossil Crinoid forming the subject of this commu- 

 nication received a MS. name from the late Prof. Edw. Forbes, 

 who dedicated it to his friend the Rev. Osmund Fisher, by whom 

 it was procured from the Kimmeridge Clay near Weymouth, and 

 liberally presented, with numerous other interesting fossils from 

 the neighbourhood, to the Dorchester County Museum. On 

 visiting that Museum, I found that it had never been described or 

 figured, and have therefore drawn up the following description, 

 with illustrative figures, of this interesting species. 



Class ECHINODERMATA. 



Order Crinoidea. Genus Pentacrinus, Muller. 



Pentacrinus Fisheri, Forbes, n. sp. PI. I. fig. 1 a. 



P. calyce parvo laevi ; articulis basalibus clypeiformibus, quinque ; 

 articulis radialibus amplis, quinque; articulis brachialibus amplis, 

 triangularibus, quinque ; brachiis decern bifurcatis, articulis cunei- 

 formibus, alternis ; pinnulis articulis octo ; columna pentagonale ; 

 ramulis articulis contiguis. 



Diagnosis. — Calyx small, smooth, and composed of five shield- 



* Communicated by the Author ; having been read before the Dublin 

 University Zoological and Botanical Association, December 16, 1859. 



