46 p. H. CAEPENTEE ON" COMATTJL-ffl EEOM 



others, are separated from the centrodorsal by the small triangular 

 ends of the basal rays. The precise nature of these " interradial 

 radials " puzzles me a good deal, and I prefer for the present to reserve 

 my judgment about them. 



Let us now pass on to the Comatulce which I have to describe. 



1. Antedok paradoxa *, Goldf. sp. Plate V. fig. 1. 



Glenotremites paradoxus, Goldf. Petref. Germanise, i. p. 159, Taf. 

 xlix. fig. 9, Taf. li. fig. 1. 



Antedon paradoxus, Schluter, Zeitsch. d. deutsch. geol. Gesellsch. 

 1878, p. 42. 



The Museum of Practical Geology contains two specimens of a 

 Chalk Oomatula which agrees very closely with Glenotremites para~ 

 doxus as described by Goldfuss and Schliiter. The centrodorsal is 

 hemispherical, with a deepish hollow at the pole. The bottom of 

 this hollow is occupied by a five-rayed impression, which is far more 

 distinct in the smaller specimen than in the larger. The cirrhus- 

 sockets are in 10 vertical rows, each row consisting of 2-4 sockets 

 more or less alternating with those of adjacent rows. The characters 

 of the sockets, as described by Goldfuss, are rather peculiar. " They 

 are pierced in the centre by an oval hole, which has a slight elevation 

 at each side, and is apparently only absent from a few of the upper- 

 most pits \i. e. sockets]. The remaining surface of the pits, as far 

 as their margin, is marked by very fine grooves, which here and there 

 are continuous with those of the adjacent ones." Yery similar 

 cirrhus-sockets occur in some of Schliiter's new species, but only in 

 the Cretaceous ones ; and even in these the central perforation has 

 not the oval or keyhole-shape that it has in A. paradoxa^ and 

 another species {A. rugosd) from the English Chalk, which I shall 

 describe immediately. 



The basal grooves on the ventral surface of the centrodorsal are 

 rather deep, and of an elongated pyriform shape, just as in Goldf uss's 

 smaller figure (Taf. li. fig. 1). Their sides are more or less 

 distinctly plicated, showing traces of very minute ridges and furrows 

 (PI. Y. fig. 1), which run somewhat obliquely to the axis of the 

 grooves, and give them exactly the appearance represented in 

 Goldfuss's figure. This, I believe, is the real nature of the " paarweise 

 gegen liber stehende Poren " which Goldfuss imagined himself to have 

 discovered, so that he was led to describe the grooves as " Felder 

 der Piihlergange." 



I regard these markings as rather more characteristic of this 

 species and its allies than Schliiter seems inclined to admit. He 

 says " there are, it is true, some irregular punctate impressions in 

 the original specimen, but they are not perforations. They are 

 unimportant and accidental, and have nothing whatever to do with 

 ambulacral pores." Similar markings occur more or less distinctly 



* gchluter uses Antedon as a masculine name. I have given reasons else- 

 where {"Actinometra," p. 16) for preferring to follow Pourtales, who makes it 

 feminine. The latter course seems to he the more correct from an etymological 

 point of view (' Nature,' vol. xv. p. 366). 



