134 Revieics — JBather's Crinoidea of Gotland. 



ever, is easily overcome by the author in pronouncing the pinnules 

 to be "false," on the ground that though their structure is similar 

 to that of true pinnules, yet they are articulated in the middle, 

 instead of at the further end of the brachial ! 



In the family Calceocrinidee are included the following genera : 

 Castocrinus, Eingueberg, Euchirocrinus, M. and W., Calceocrinus 

 (Hall), Ringueberg, and Salysiocrinus (Ulrich), Bather. These four 

 genera are considered to represent an evolutionary series and not 

 divergent branches, so that many forms of an intermediate nature 

 might be expected to occur. A list of all the known species of 

 these genera is given. Calceocrinus is the only genus of the series 

 known in Gotland ; one species had been described by Angelin, 

 and to this six new ones are added by the author. One of the new 

 forms, G. pinnulatus, diifers from the type and all the other species 

 in this genus in the possession of pinnules on the arms and in the 

 plan of arm-branching. 



Of the suborder Dicyclica, the first family treated is the Dendro- 

 crinid^, which is distinguished from the Decadocrinidee by the 

 continuous dichotomy instead of the single bifurcation of the arms, 

 and from the Cyathocrinida3 by the constant occurrence of a 

 plate in the anal area, the wide radial facet, and the more delicate 

 tegmen. This family is divided into the Dendrocrinites and the 

 Scaphiocrinites ; in the former are included the genera Merocrinus, 

 Ottawacrinus, Dendrocririus, Mastigocrinus, Uoviocrinus, and Pariso- 

 crinus. Of these, only Homocrinits, Hall, is represented in Gotland 

 by one species ; the genus had only previously been known in 

 America. 



The family Euspirocrinidas definitely includes only the genus 

 ^tispirocrinuH, Aug., but two other genera, Closterocrinns and Am- 

 pheristocrinvs, are associated with it provisionally. Euspirocrinus 

 is described as possessing the dorsal cup of an advanced Dendro- 

 crinite with the tegmen of a Cyathocrinite, whilst its arms might 

 belong to either of these groups. The character of the tegmen of 

 the calyx is well shown in an example of E. spiralis, figured by 

 Angelin (Icon. pi. iv. figs. Id. e), and reproduced on a larger scale 

 by the author (p. Ill, fig. 14). In this the food-grooves from the 

 arms are continued along wide channels formed by the depressed 

 edges of the large heart-shaped deltoidal plates, and these channels 

 pass directly into the peristome, which is bounded on four sides 

 by the deltoids and on the fifth b}' the madreporite plate. The 

 channels are covered over by the ambulacral plates, which are fitted 

 into small depressions in the deltoids. 



The family Decadocrinidse, previously proposed by Mr. Bather, 

 may be divided into several series, but only one, Botryocrinites, is 

 represented in the Gotland Silurian. This division includes the 

 genera Botryocrinus, Barycrinus, Vasocrinus, Atelestocrinus, and a 

 new genus, Gothocrinus, which is said to possess a Dendrocrinus cup 

 with Botryocrinus arms. Under Botryocrinus, Ang., in addition to 

 B. ramnsissimns, Ang., the author also places Sicyocrinus cucurhi- 

 taceus, Ang., distinguished by its peculiarly curved ventral sac, 



