CARADOCIAN CYSTIDEA FROM GIRVAN. 363 



^ 10. Further, the species fall into two very liniited groups. First, that division of 

 the Amphoridea to which Dr 0, Jaekel (1901) has given the name Heterostelea, 

 placincr them in his newly invented Class the Carpoidea and not in the Cystidea : and 

 secondly, a single Family, the Cheirocrinidae of the Order Rhombifera. The genera 

 represented are : — 



Amphoridea Heterostelea — 



Fam. : Dendrocystidae spp. 



Dendrocystis 1 



Fam. : Cothurnocystidae 



Cothurnocystis n.g. 2 



Rhombifera — 



Super-Fam. : Glyptocystidea 

 Fam. : Cheirocrinidae 



Cheirocrinus 2 



Pleurocystis 4 



§ 11. [t will be observed that throughout the memoir, except in quotations, the 

 cumbrous termination -ites is dropped. Since full reference is always made to the 

 original spelling of every name discussed, this procedure will mislead no one. It may, 

 at the worst, be regarded as a contraction of practical utility. 



Discussions of the geological and biological relations of this Cystid fauna follow the 

 systematic description {§§ 559, 578). 



§ 12. For the opportunity of studying the Girvan specimens, my thanks, as already 

 explained, are due to Mrs Gray. But for generous aid in supplying me with material 

 for comparison I have to thank many kind friends whose services are recorded in the 

 body of the work : they are Prof. Anton Fritsch and Dr J. Perner of Prague, 

 Prof G. Holm of Stockholm, Prof. 0. Jaekel of Greifswald, Mr Walter R. Billings 

 of Ottawa, Dr F. L. Kitchin and Mr H. A. Allen of the Geological Survey, 

 Prof Hughes and Mr H. Woods of Cambridge, and Prof. Sollas of Oxford. I am also 

 indebted for help and information to Mr Cowper Reed, Prof. Grenville Cole, 

 Mr R. Bullen Newton and other colleagues of the Geological Department, 

 Dr J. E. Marr, and, less directly, a number of other friends and correspondents. Much 

 of the work has been carried out at the Natural History Museum as part of the 

 preparation for an official Catalogue, and I would express here my obligation to the 

 Trustees of the British Museum for permitting the publication of this matter, and to 

 Dr A. Smith Woodward, the Keeper of the Geological Department, for facilitating 

 the progress of the work. Dr John Horne, who communicates this memoir to 

 the Society, has in more than one respect proved a friend in need, and it is a par- 

 ticular pleasure to me to have this opportunity for grateful acknowledgment of his 

 kindness. 



