330 ROBERT TRACY JACKSON ON ECHINI. 



with pores showing in part only. A small triangular ocular lies next to genital A and is similar 

 in size and appearance to the small oculars shown in text-fig. 243. 



The specimen from Kirkby Stephen and now in the York Museum, is the original described 

 by de Koninck (1869, 1870) as Palaechinus sphaericus. De Koninck's description and figures 

 have entered much into succeeding publications (footnotes, pp. 303, 317, 326). In considering 

 these, I found discrepancies and characters which I could not account for, and at my request 

 my friend Dr. F. A. Bather, most generously came to my aid, borrowed the specimen, devel- 

 oped it with great pains, and sent me the accompanying photographic figure and drawings 

 (Plate 35, fig. 7; text-figs. 240-243). I w^ould express to him my heartiest thanks for this most 

 friendly and important service. x4.s seen by the figures, the specimen is not a Maccoya sphaerica 

 (M'Coy), and does not belong to that genus, the ambulacra being quite different from those of 

 sphaerica (Plate 34, figs. 4-10) and from M'Coy's description (p. 318). Further, oculars are 

 present, not absent, as claimed by de Koninck, a very important point, for now one can say that 

 they are not absent in any known regular echinoid. The following description is taken from 

 Dr. Bather's critical and painstaking notes. This specimen in character is close to the British 

 Museum specimen from Llysfaen, and it is possible that they may form a species distinct from 

 lacazei, but as they agree with it structurally, they are included here. 



Dr. Bather writes, "The specimen was originally in the collection of Mr. Edward Wood, 

 F. G. S., of Richmond, Yorkshire, and came as part of the Reed Collection to the Museum of 

 the Yorkshire Philosophical Society. Thence it was kindly lent to me by Mr. Oxley Grabham. 

 It was at once obvious that de Koninck's sketch was not merely diagrammatic, but inaccurate 

 in several important particulars. It was not, however, clear that his statement as to the 

 oculars was incorrect. Indeed, it took me several weeks of careful preparation before all the 

 questions asked me by Dr. Jackson could be answered with the aid of a good lens under the most 

 favourable conditions of illumination. The wisest course, therefore, seems to be to draw up a 

 fresh description of this interesting specimen. 



"The echinoid lies at the corner of a fragment of pinkish grey limestone, weathering to 

 a darker red of almost haematite tinge. This deep color is now, however, destroyed by the 

 methods of preparation. The matrix can never, I think, have borne to the fossil quite the 

 relations shown in de Koninck's figure. In that figure the upwardly directed ambulacrum is 

 the anterior one, and the left-hand boimdary of the matrix now passes upwards in continuation 

 of its median line. From the angle where the matrix joins this amliulacrum to the limit of the 

 posterior interradius, the length of the exposed test is 60.7 mm. The distance from the same 

 point to the apical pole is 44 mm. The distance from the apical pole to the visible end of the 

 right anterior ambulacrum is about 36 mm., and to the visible end of the adjacent right posterior 

 interradius about 26 mm. It may be inferred from these measurements that the diameter of 

 the test was about 55 mm., and that its height was rather greater. 



