ENGLISH Uri'KK SILURIAN OSTRACODA. 135 



the genera ; and in March and June, 1887, lie 

 published in the same magazine, illustrated by six 

 plates, a description of species belonging to the 

 genera Macrocypris, Pontocypris, Bythocypris, Cythere, 

 Priviitia, Cytherella, Thlijjsiira, Octonaria, Bollicif 

 Moorea, Xestoleberis, and jEchmina* Five new 

 genera, 57 new species, and 12 new varieties were 

 described from the two collections. 



In the avitumn of 1888 I again visited the English 

 Silurians, examining localities I had not before 

 searched, and collecting material from 44 diiferent 

 places. Thirty-seven of these collections were found 

 to contain Ostracoda in greater or lesser abundance, 

 as shown in the Abstract appended to this paper. 

 As was to be expected from the examination of a 

 formation which had only before been worked for 

 Ostracoda to a small extent by the late Dr. HoU 

 and the late Lieutenant Henry Adrian Wyatt-Edgell, 

 a number of new forms turned up, but these have 

 not been looked over. There are at present known, 

 from the English Silurians, 16 genera and 94 sj)ecies 

 and varieties of Ostracoda ; but when all the 

 localities become thoroughly wrought up, we may 

 expect a list of perhaps about 150 species. 



Character of the Strata. 



Neither in any of the Silurian Limestones, nor in 

 the rotted cavities contained in the same (which, it 

 may be remarked, are exceedingly few in the 

 Wenlock Limestone, but more numerous in the 

 Aymestry Limestone), have I been able to detect a 

 single entomostracan ; and all Mr. Vine's specimens, 

 like my own, were obtained from the shales. It is 

 not unlikely, however, that Ostracoda may yet be 

 found in the limestone, as we know that they are 

 often abundant in the Scotch Carboniferous Lime- 

 stones. Many of the Silurian Limestones are very 

 crystalline, and in these we can scarcely expect to 

 find Ostracoda; but some of the bands, especially 



^IbicL, vol. xix. (Fifth Scries), pp. 179-194, 400-41G; pi. iv.-vii , xii., xiii. 



