1886.] NATURAL SCIENCES OP PHILADELPHIA. 181 



Family XXIII. ENCRINID^ Pictet. 



J. S. Miller refers the genus Encrinus, together with Penta- 

 crinus, to his Articulata, Poteriocrinus to his Semiarticulata. 

 Zittel, and after him De Loriol, to the Articulata of Miiller ; 

 while they refer the closely allied Poteriocrinus to Miiller's Tes- 

 sellata. The mode of articulation is identical in Encrinus and 

 the later Poteriocrinidae, as pointed out in our general remarks 

 on the Fistulata, and our notes on the Poteriocrinidse. A sepa- 

 ration, therefore, in the sense of either Miller or Miiller, cannot 

 be eai-ried out practically. A ventral covering was never found 

 to be preserved in Encrinus, and as the same thing happens to 

 be a rule among all fossil Neocrinoidea, it was postulated that 

 this genus had an open perisome, and as such was a Neocrinoid. 

 However, the ventral surface is also unknown among the Poterio- 

 crinida?, which are universally regarded as Palseocrinoids. Neither 

 is the absence of azygous plates in the dorsal cup exclusively 

 found among Neocrinoidea we need only allude to Codiacrinus, 

 Ceriocrinus and Erisocrinus nor the presence of two brachials 

 (three radials), which was pointed out by Carpenter a good dis- 

 tinctive character. The latter is a very common occurrence among 

 tlie Poteriocrinidie, among which we failed even to make it a 

 generic distinction. We are willing to admit that Encrinus con- 

 stitutes a transition form toward the Neocrinoidea, it is even 

 possible that in the adult the interradials became partly or wholly 

 resorbed, but it is otherwise so closely connected with the Poterio- 

 crinidffi that we must regard it a Palaeocrinoid or place also the 

 Poteriocrinidge among the Neocrinoidea. 



Pictet, and after him Dujardin and Hupe, placed Encrinus 

 under the Pycnocrinidees, which they subdivided into Encriniens, 

 Apiocriniens and Pentaci'iniens. This division was accepted by 

 De Loriol in his work on the Swiss Crinoids, but in his later 

 monograph on the Crinoids of France he followed Zittel, who 

 made it the type of a distinct family of the Neocrinoidea. All 

 writers preceding us, with the exception of Zittel, described En- 

 crinus with 3X5 radials, although the two upper plates are 

 laterally free, and morphologically and functionally identical 

 with the brachials of the Poteriocrinidae. 



We agree with De Loriol and Zittel that Yon Meyer's genus 

 Chelocrinus, which is based on species having a second bifurca- 



