Correspondence — Mr. F. A. Bather. 



135 



cTEsneux may be the arenaceous equivalent of the more slialy beds 

 of Mariembourg. 



Now ray argument was that Dinocystis Barroisi, being what was 

 usually called an Agelacrinus, was with little doubt the same as 

 the " Agelacrinus" which Mourlon cited in 1881 (" Geol. de la 

 Belgique," ii, p. 23) from " Assises de Montfort et d'Evieux " ; and 

 therefore that our specimens of D. Barroisi also came from tliese 

 beds, " the uppermost member of the true Upper Devonian." Pro- 

 fessor Dewalque states that, " for important reasons," he believes 

 the Agelacrinus of Mourlon, 1881, to be the same species as a certain 

 " asterie," to which Mr. Mourlon referred in 1875 as being in 

 " collection Malaise." This "asterie," according to Prof. Dewalque, 

 is a specimen of his Protaster Decheni, from the Assise d'Evieux. 

 If these beliefs were justified, it would follow that Dinocystis 

 Barroisi was not the same as the Agelacrinus of Moui'lon, and it 

 would be referred to the same horizon on no better evidence than an 

 inaccurate dealer's label. 



Since the validity of Professor Dewalque's criticism entirely 

 depends on " important reasons," we should be warranted in dis- 

 regarding it until those reasons have been published. But the high 

 authority of my critic, no less than the difficulty of attributing so 

 incomprehensible an error to the learned director of the Service 

 Geologique de Belgique, has led me to investigate the question 

 afresh. 



The results more than justify my former inference. 



Dinocystis Barroisi : pliotograpliic reproduction (reduced to f ) of a pencil -drawing 

 made for Mr. Mourlon in 1881, from tlie specimen then referred by him to 

 Agelacrinus. The position of the anus was not observed by the draughts- 

 man ; it may well have been in the rather irregular interradius to the right 

 in the drawing of the actinal surface. 



Professor C. Malaise kindly informs me that the above-mentioned 

 " asterie " is still in his collection, that it is a specimen of Protaster 

 Decheni, Dewalque, and that the bed at Walcourt from which it 

 came belongs, in his opinion, to the Assise d'Esneux (not the 

 Assise d'Evieux, to which the tj^pe-speciraen is now referred). 



