PROF. T. R. JONES ON SOME PALEOZOIC OSTRACODA 



of Nova Scotia; PI. I. figs. 11, 13, 14, and PI. II. figs. 2-5 and 

 7-13, are from the Hamilton Group of Lake Erie. 



4. The specimens shown by PI. lY. figs. 1-3, belonging to the 

 " Utica Slate" series, were given to me by Mr. John Young, F.G.S., 

 of Glasgow, who had them from Ontario, Canada. 



5. An interesting series of five Lower- Silurian (Ordovician) 

 species, from near Welshpool, Montgomeryshire (PI. lY. figs. 4-13), 

 comprising a characteristic Cincinnati species, were sent to me by 

 Mr. J". Bickerton Morgan, F.G.S., of Welshpool. 



6. Lastly, PI. lY. figs. 14, 15, represent a rare Palaeozoic Cythe- 

 roid Ostracod from Kildare, Ireland, collected by Mr. Joseph 

 Wright, F.G.S. 



7. The specimens are described as nearly as possible in the order 

 of their natural relationship ; and thus, besides adding to the known 

 forms, they illustrate the modifications exhibited by the genera and 

 species of these minute bivalved Crustaceans, both in limited dis- 

 tricts and in different regions, as indicated in the following List 

 (p. 3) of 44 species (with notable varieties) belonging to 11 genera. 



Range of some Palceozoic Genera of Entomostraca. 



*Priinitia 



Aparchites ., 

 *Isochilina ., 

 itLeperditia ., 

 ^Primitiopsis 



Entomidella 

 ^Entomis 



Bolbozoe 



*^chnjina.... 



Placentula . 



*Bollia 



*Kloeclenia ., 

 *Beyrichia 



Kirkbya 



*Strepula 



Moorea 



Thlipsura.,.. 



Octonaria...., 



Bursulella . 



Macrocypris 



Pontocypris., 



Bairdia .... 



Bythocypris. 



Cy there .... 

 #Xe8t,oleberis. 



Cytherella . 



Cytherellina 



*H 



H 

 *H 

 H 



*H 

 H 



j^OTE. — H means that the genus is represented in the "Hamilton Group 

 of the United States. 

 jDf the 11 genera marked *, 44 species are described in the present paper. 



