BOTHRIOCIDARIS. 243 



nine plates in a column according to Schmidt, and nine as seen in Plate 8, fig. 1. The surface 

 of these plates is finely granulated, but with no perforate tubercles, indicating that in this 

 species there were no large spines, possibly no interambulacral spines at all. If the latter, 

 it is a unique condition in Echini. There are two rows of peristomal ambulacral plates, the 

 second being in contact with the ventral border of the primordial interambulacral plates. The 

 oculars are large, of which the ocular considered III is the largest. Each plate bears two or 

 three tubercles. Oculars IV, V and I, II are in contact (Plate 1, fig. 6), but IV, III and II, 

 III are separated so that genitals 2, 3 reach the interambulacra. Thus it is structurally bi- 

 laterally symmetrical through the axis III, 5, but this may be a mere coincidence. Four small 

 genitals are in place, but genital 5 is wanting; 2 and 3 reach the interambulacra as in B. globulus, 

 but the others are shut out by the contact of the oculars. Each genital bears a small per- 

 forate tubercle. Considering these plates as genitals, there are three other plates within the 

 apical disc that may be considered as plates of the periproct. This species differs from the 

 other two in that there are no perforate tubercles on the interambulacral plates, and it is inter- 

 mediate between B. archaica and B. globulus in the lateral contact of the ocular plates (p. 87). 



The type is from the Jeweschen Schicht, Ordovician, Nommis, Esthland; a second speci- 

 men, the original of Plate 8, fig. 1, is from the Diluvial-Geschichte, Ordovician, Rostov, Russia. 



Loven (1883, p. 57) described and figured in this species, presumably the type specimen, 

 long cylindrical bodies having one end in close relation to the ambulacral pores. He took these 

 for tube-feet, and said that they even showed traces of having their tubes strengthened by 

 arcuate spicules. It certainly is a remarkable condition of fossilization if these are tube-feet. 



In the figure which I published (1896, text-fig. 4, p. 234) of this species, the error was 

 made of taking the perforation of tubercles for ambulacral pores, so that these were repre- 

 sented incorrectly, in a horizontal plane instead of superposed. The same mistake was made 

 by Gregorj^ (1900). The photographic figure (Plate 8, fig. 1) is taken from a cast that was 

 made by Dr. Jaekel and which he kindly gave me. It shows enlarged the general appearance 

 of the species, relative width of plates, and the whole length of one interambulacrum. The 

 interambulacral areas are colored to differentiate them. 



Bothriocidaris globulus Eichwald. 

 Plate 1, figs. 7-9. 

 Aldrovandus, 1618, p. 136, fig. 5. 



Bothriocidaris globulus Eichwald, 1860, p. 55, Plate 32, figs. 22a, b, but not fig. 23; Schmidt, 1874, p. 40, 

 Plate 4, figs. 2a-2c; (pars) Jaekel, 1894; (pars) Jackson, 1896, p. 238; (pars) Klem, 1904, p. 15; 

 (pars) A. Agassiz, 1904, p. 79; Lambert and Thiery, 1910, p. 118. 



Botriocidaris globulus Neumayr, 1881, p. 152. 



Eichwald's original figures and description are not very detailed, but Schmidt gives an 

 excellent description and figures of this species, from which my account is taken. Test globular. 



