360 r>R F. A. BATHER. 



defined by me in Lankester's " Treatise on Zoology," 1 900.* This, while excluding the 

 Edrioasteroidea, includes forms that have been removed from the Cystidea, by Haeckel 

 as Amphoridea, and by Jaekel as Carpoidea. 



§ 2. Though written in order to describe Girvan material, the memoir has grown to 

 little less than a monograph of the genera dealt with, and even includes the description 

 of a new species from Bohemia. For this no apology is required. When a group of 

 organisms has recently received adequate revision, new forms may on occasion be 

 merely described and referred to their systematic position. In the present instance, 

 prolonged study of allied species and genera proved a necessary preliminary to 

 the understanding of the Girvan fossils, and if the descriptions of the latter are 

 to be intelligible the reader must first be placed at the same point of view as 

 the writer. 



§ 3. On the other hand, there are excluded from the memoir various remains, 

 apparently of Cystidea, that do occur in Girvan but are for the present incapable of 

 precise determination. 



§ 4. To show the Geological Distribution in Girvan of all the Cystid remains, both 

 described and undescribed, I adapt a portion of the Table of Girvan Strata drawn up 

 by Messrs Peach, Horne, & Macconochie (1901, p. 429).* 



Llandovery — Newlands Series. 



3. Camregan Group. Bargany Pond Burn, plate of a Glypto- 

 Grits, limestones, and shales. cystidean (?) 



Rastrites inaximus. 

 2. Saugh Hill Group. Woodland Point, 1 plate and 1 ? base of 



Flagstones and shales. ? Cystid. 



Monograptus spinigerus, 



Rastrites peregrinus. 

 1 . Mulloch Hill Group. 



Sandstones and shales ; conglomerate. 



Dij)lograptus acuminatus. 



Caradocian— Ardmillan Series. 



5. Drumniuck Group. Thraive Glen, spp. of Dendrocystis, 



Mudstones, Starfish Bed. Cothurnocystis, Cheirocrinus, Pleuro- 



Dicellograptus anceps. cystis. 



4. Barren Flagstone Group. 

 Diplograptus truncatus. 



* AVorks and papers to which veference is made in the text will be found in the list (§ 615) under the names 

 of their respective authors, the writings of each author being in order of date. 



