Prof, De Koninck. — New British Echinoderms. 261 



These three plates, united, form on each side of the fossil a radius 

 similar to that of the Crinoids proper. The second range is com- 

 posed of four plates, united symmetrically in pairs, and alternating 

 ■with the plates beneath. In this way the suture becomes median, 

 and it is on this suture, and towards the middle of the two centre 

 plates, that the anal aperture is seen ; it is circular and about three 

 millimetres in diameter. The series which follows that enclosing 

 the anal plate is only composed of three pieces, a little longer than 

 broad, alternating with those which serve as their supports, whilst 

 the last range, also composed of three small plates, is placed imme- 

 diately upon the preceding. All these plates are perfectly smooth 

 on their external surface.^ 



The posterior side is concave over its whole extent, except near the 

 base, where a subconic median lobe projects, as is shown in Figs. 3 

 and 4, PL VII., which accompanies this paper. It results from this 

 arrangement that the two sides of the test are very much compressed 

 together, and leave but a small space for the soft parts of the animal. 



In spite of the attention with which I examined the specimen 

 figured, which was the only one on which the posterior surface was 

 visible, I was unable to discover any division into plates on that 

 side. It would indeed be surprising, however, if it were composed 

 of only one piece.^ I am driven to believe that this appearance is 

 only due to the state of fossilization, by which all traces of separate 

 plates have vanished. I shall make the same observation concerning 

 the base. It is furnished with a slight oval depression, limited by a 

 narrow border, which leads one to suppose that the animal has been 

 supported by a stalk. Seen from beneath the base it presents the form 

 of a crescent, see Plate YII., Fig, 4. I have dedicated this species 

 to my friend, the late lamented Professor Edward Forbes. 



I shall conclude this paper by the description of a new species of 

 Haplocrinus, which I propose to call H. granatum. 



This genus was created by Steininger in 1834, for a small species 

 of Crinoid common in the Eifel, but which Goldfuss had already 

 described under the name Engeniocrinites mespiliformis.^ Until now, 

 this last species, and that described by Prof. James Hall, under the 



1 When examined with a pocket magnifying glass, the plates of nearly all the 

 specimens in the British Museum, now upwards of twenty in number, show a finely- 

 striated ornamentation running in an obliquely-transverse direction across their sur- 

 face. Probably the specimen examined by M. de Koninck may have been much 

 rubbed upon its surface. In the publications of the Geological Survey of Canada, 

 Decade III., "Figures and descriptions of Canadian organic remains," Montreal, 

 1858, p. 72, Mr. E. Billings, the accomplished palteontologist to that Survey, has 

 figured in a small woodcut and described an anomalous and imperfect Cystidean, 

 under the name of Ateleocystites Muxleyi. From the figure and description we are 

 inclined to think it may hereafter be shown to be the " posterior" surface of a cys- 

 tidean, identical with M. de Koninck's Placocystites Forbesianus ; the more so as 

 the plates are described by Mr. Billings as tranversely striated. But as the Canadian 

 specimen is very imperfect, we think it would be very hazardous to assume from the 

 figure alone that Placocystites (de Koninck, 1869) was synonymous with Ateleocystites, 

 Billings, 1858.— Edit. 



2 One of the specimens in the Museum shows at least nine plates on its posterior 

 surface. — Edit. 



3 Goldfuss Petrefact. Germ. Tome i. p. 213. PI. Ixiv. Fig. 6. 



