Revieics — Wachsmuth 8f Springer's Monograph on Crinoids. 421 



arranged as in Stenocriniis," which is now called Ueterocrinus, and 

 has three compound radials. Anomalocrinus also was formerly 

 described by Wachsmuth and Springer (ReYision, iii, p. 211) as 

 having two or three compound radials, the " left postero-lateral " 

 being "either simple or bisected vertically." They subsequently 

 figured it with no less than four compound radials,^ a figure that 

 also conflicts with their present statement that at least two of the 

 radials in every crinoid are always simple (p. 71). Even more 

 unwarranted is their next remark: "Neither do we find [in 

 Monocyclica] any remai'kable development of certain radials, except 

 when these are compound." The large left posterior and anterior 

 radials of Pisocrinus, Triacrinus, and Haplocrinus are not compound, 

 but their modification is undoubted, and similar enlargement is 

 very remarkable indeed in the Calceocrinidce and in Mycocriaus and 

 Catillocrinns. 



But if they will not admit these facts in Monocyclica, my critics 

 try to maintain that they do occur in Dicyclica. " Bather," they 

 continue, " claims that among the Dicyclica departures from the 

 pentamerous symmetry of the cup plates occur only in the right 

 posterior radial. [When and where I made this preposterous claim 

 is not stated. I said, " horizontal bisection " occurred only in 

 r. post. R.] Exceptions to this, however, are found in Atelestocrinus 

 and Nanocrinus, in which the symmetry is disturbed by the anterior 

 radial, and in the latter genus by the right antero-lateral together 

 with the anterior." This is a curious way of expressing the fact 

 that in those genera the anterior radial is smaller than the others 

 and bears no arm, a fact which is not in either of the categories 

 under discussion. 



But enough of controversy ! Let me state what I now believe to 

 be the facts of the case. Thirty-one genera may be referred to the 

 Monocyclica Inadunata. Of these, twenty diverge from the normal 

 symmetry to a greater extent than by the introduction of anals, viz., 

 ten ^ through the horizontal bisection of certain radials other than 

 the right posterior (usually the right and left anterior radials), while 

 the remaining radials often increase in width ; eight ^ through such, 

 increase in width of certain radials (usually 1. post. R. and ant. R.), 

 often accompanied by a variation in the number of arms directly 

 springing from the radials ; one * by disappearance of a radial 

 (an occurrence also found in some of the other genera ^) and 

 apparent increase in the number of arms springing from the radials 

 (as in some other genera''). The proportion of forms asymmetrical 

 in the manner described would be larger if only Palaeozoic genera 



1 " Perisomic Plates": Froe. Acad. Nat. Sci. Philadelphia, 1890, pi. x, fig. 10. 



"^ Ueterocrinus, Ectemcrinus, Ohiocrinus, Anomalocrinus, Serpetocrinus, Casto- 

 crinus, Euchirocrinus, Calceocrinus, Sulysiocrinus, Haplocrinus, and perhaps 

 Fhiinocrinus. 



^ Hybocystis, Hoplocrinus, Pisocrinus, Triacrinus, Calycanthocrinus, Mycocrinus, 

 Catillocrinus, and Allagecrinus. 



* Zophocrinus. 



* e.g. Tetracrinus, and probably Herpetocrinus. 

 ^ e.g. Catillocrinus, Alycocriniis. 



