GEOLOGY AND MINEKALOGY. 303 



the possession, amongst other peculiarities, of more than two ranges of plates 

 ath>ve the pelvic range. Mr. Billings proposes, we believe, for this new genus, 

 the name of Malocyaiites. 



The following list of the principal genera of Cystidece at present known, with 

 their leading characteristics, etc., may not perhaps be unacceptable to some of our 

 readers. 



Cystidece : — principal genera : 



1. Echinosphcerites, Wallenberg (Sphemnites) : — Cup of numerou? plates with 

 irregularly distributed pores. The principal species comprise: E. Ballicus, E. 

 Aurantium, E. Pomum,* E. Punctatus, and E Granulctus. 



2. Caryocystites (Von Buch): — Cup of five ranges or series of plates. Pelvic 

 plates 2 + 2. Iucluded by some palaeontologists in Echinosphcerites. 



3. Echino-encriuHes, Meyer (Sycocystites, V. Buch ; Gonocrinites, Eichwald,) 

 cup of 4 ranges of plates. Felvic range: 3 + 1. Other ranges : 5, 5, 5. Pores 

 bordering rhomboidal arens. Only two openings (?) : perhaps one divided to serve 

 both for anal and ovarian orifice. 



4. Glyptocystites (Billings :) — Cup of 4 ranges. Pelvic range : 3 + 1. Other 

 ranges: 5,5.5, Five (= 4 + 1,) attached aims. Three openings : the ovarian 

 opening without valves (?), and distant from the mouth. Numerous pore-areas, or 

 " pectinated rhombs." We have placed this genus here, because if not identical 

 with Echino-encrinites, it is evidently closely allied to it. The numerous pore- 

 areas constitute its great distinguishing feature. Where these pore-areas occur 

 in other genera, more than three, or three pairs, are never present. 



5. Apiocystiles (E. Forbes.) Cup of 4 ranges. Pelvic range of 4 plates. 

 Four attached arms in shallow grooves. One American species (A. clegans) : 

 Hall, Pal, New York, vol. II, page 241,) from the Niagara group. Perhaps identi- 

 cal with the A. Pentremiorides of the English survey. 



6. Prunocystites (E Forbes.) 7. Pseudocrinites (E. Forbes.) 



8. HemicosmUes (Von Buch): — Cup of 4 ranges. Pelvic plates 4. Plates of 

 the other ranges : 6, 9, 8, (at least in the known species.) The three openings in 

 the top range. 



9. Pleidrocystites (Billings :) — Large plates on only one side of the cup. On the 

 other side a large opening, probably covered by an integument strengthened by 

 numerous small plates. Pelvic range of six plates (=2 + 2 + 2.) Second half 

 range of three large plates. Third half-range of four plates. Top range (entire) 

 of ten small plates carrying the two arms. Several species from the Trenton 

 limestone of Ottawa. 



10. Gallocystites (Hall:) — Cup of 4 ranges. Pelvic range of 4 plates (=2 + 1 + 1.) 

 Second range of 8 plates. Five attached arms. Stem of very thin joints, (at least 

 in the known species : — V. Pal, New York, vol. 2, page 238). One species O. 

 Jewettii, (Hall) from Niagara group. 



11. Malocystites : — Mr. Billings' new genus alluded to above. 



12. Cryptocrinites, or Orypiocrinus (Von Buch) : — Cup of three ranges. Three 



* E. Poinum is viewed by some authors as the type-form of a distinct genus (Sphcsronites, 

 an old name revived,) characterised by the presence of two pores, in place of several, on each 

 plate.— B. J. C 



