348 Bibliographical Notices. 



the recent and fossil Neocrinoidea comparisons of the greatest 

 interest and importance may be drawn. The living stalked Neo- 

 criuoids at present known belong to the following genera and 

 families : — Fam. Holopidae : Holopus, d'Orb. (1 sp.). Fam. Hyo- 

 crinidae : Hyocrinus, Wy v. Thorns. (1 sp.). Fam. Bourgueticrinidae : 

 Bathycrinus, Wyv. Thorns. (4 sp.), Rhizocrinus, Sars (2 sp.). Fam. 

 Pentacrinidae : Pentacrinus, Miller (9 sp.), Melacriiius, Carpenter 

 (15 sp.). 



The fossil Holopidae are represented by "Micropocrinus of the 

 Italian Miocene, Qyaihidium in the Chalk of Faxoe, the singular 

 Gymnocrinus in the Oxfordien of France and Switzerland, and, 

 lastly, in the Middle Lias Cotylecrinus and Euclesicriniis ; while 

 Edriocrinus, from the Upper Silurian and Devonian, a type much 

 resembling Holopus in character, is a proof of the great antiquity 

 of these sessile Crinoids." The Hyocrinidae, a family established by 

 the author for the reception of the single genus Hyocrinus, have no 

 fossil representatives. This genus had been placed by De Loriol 

 and Zittel in the family Plicatocrinidae, in association with the genus 

 PKcatocrinus ; but its present separation on structural grounds 

 appears to be fully warranted. Of the Bourgueticrinidae " we have 

 no certain evidence of the occurrence of the typical genus Bourgueti- 

 eriniis in other than Cretaceous rocks; though stem-joints which 

 have been referred to this genus occur both in Jurassic and in 

 Eocene deposits. It is not unlikely, however, that they belong to 

 Thiolliericrinus or to Rhizocrinus respectively.'' " And some of the 

 stem-joints hitherto referred to Rhizocrinus or to Bourgueticrinus 

 may possiblj r belong to Bathycrinus, no calyx of which has yet been 

 found in the fossil state." " The Pentacrinida3 are remarkable for 

 their long geological history. The type genus Pentacrinus first 

 appears in the Trias, together with the short-lived Encrinus. It 

 persisted through the whole of the Secondary and Tertiary periods, 

 and is represented by nine species at the present time." On the 

 other hand, Extracrinus is confined to the Lias and Lower Oolites, 

 unless, as the author is disposed to think, the P. asteriscus, which is 

 found associated with Trias fossils in the Western Territories of the 

 United States, is also to be referred to this genus. Balanocrinvs 

 ranges from the Middle Lias to the Lower Neocomian. " The 

 remaining genus Metacrinus is confined to Oceania and the shallower 

 parts of the Pacific, and is at present unknown in the fossil state. 

 The general character of the fossil Pentacrinidae is essentially the 

 same as that of their recent representatives, except that they often 

 had much longer stems, which sometimes reached as much as 50 or 

 even 70 feet." 



It is obviously outside the limits of this notice to remark on the 

 different species enumerated in the Report, further than to state 

 that each form is described in the fullest detail possible from the 

 material available — varieties, affinities, and in some cases even 

 youthful characters, being carefully noted. It is interesting, how- 

 ever, to observe in passing that there appears to be ample evidence 

 that a Pentacrinite may become detached from its root-plate and 



