400 
Aug. F. Foerste 
34. Agelacrinus holbrooki, James 
35. Agelacrinus warrenensis, James 
36. Streptaster, generic characteristics 
37. Streptaster reversata, sp. nov. 
38. The thecal plates of Cystaster and Hemicystites. 
39. Hemicystites carnensis, sp. nov. 
Description of several Lepadocystinae 
40. The migration of the anus in the Glyptocystidae 
41. LepadoCystis, Carpenter, generic characteristics 
42. Lepadocystis moorei, Aleek 
43. Brockocystis, Gen. nov., generic characteristics 
44. Brockocystis tecumsethi, Billings 
45. Brockocystis clintonensis, Parks 
46. Brockocystis huronensis, Billings 
1. Introduction 
In preparing the descriptions of Thresherodiscus and Brocko- 
cystis it was found necessary to make a study of related genera 
and species. This led to an accumulation of notes, a part of 
which are presented in the following pages. Among these are 
notes on the floor plates and covering plates of the ambulacral 
rays and on the substomial chamber or cavity in various Agela- 
crinidae. While it has long beeen recognized that a new generic 
term should be proposed for the Ordovician species usually 
referred to Agelacrinus or Lepidodiscus, no new name is offered 
here since Dr. Bassler is engaged at present on a study of this 
group. 
The writer is under special obligations to Dr. E. O. Hovey, of 
the American Museum of Natural History, in New York City; 
to Prof. Stuart Weller, at Chicago University; to Prof. A. D. Hole, 
at Earlham College in Richmond, Indiana; and to Prof. S. R. 
Williams, of Miami University, at Oxford, Ohio, for the loan of 
Agelacrinidae from the Museums of which they have charge. 
Specimens have been borrowed also from the collection of Dr. 
G. M. Austin, of Wilmington, Ohio. 
It has been found possible to determine the systematic position 
of the fragmentary specimens described by Billings under the 
terms Apiocy stiles tecumseth and Apiocy stiles huronensis, species 
whose systematic position hitherto has been in question. 
The writer is under obligations also to Dr, R. W, Brock, the 
