202 ME. P. II. CAilPENTER ON THE GENTS SOLANOCUINTS 



These immature An tedons occur at both Nattheim and Schnaitheim 

 in the same beds ( Weisaer Jura, e) as A. costata. I do not think, 

 however, that they can be identified with that species, chiefly on 

 account of the differences in the characters of theradials. A side 

 view of A. costata (PI. IX. figs. 1 a, 2 a) shows not only the external 

 surface of the radials directly above the centrodorsal, but also their 

 distal articular faces, that are set at a very obtuse angle to this 

 surface. In Ant. sigillata, on the other hand, the outer surface of 

 the radials is relatively far larger than in Ant. costata ; but the 

 distal articular faces, are set on to it at such a much less obtuse 

 angle that little or nothing is visible of them in a side view (' Eu- 

 criuiden,' tab. 96. fig. 49). I know nothing like this condition 

 among the recent Comatiolce, though an apparent approximation 

 to it is seen in Quenstedt's figures 35 and 56, described as the 

 " young " of Ant. costata and Ant. scrobiculata respectively ; but 

 these figures are not distinct enough for me to make this out with 

 certainty. They also resemble Ant. sigillata in the relatively small 

 size of the basals, which is another point of difference between it 

 and Ant. costata. Many of these smaller varieties require much 

 more illustration than it was possible to give them in the neces- 

 sarily crowded plates of Quenstedt's admirable atlas. 



XII. — Antedon aspera is one of these incompletely known forms. 

 The calyx seems to be rare, though portions of the arms have 

 been found in the Swiss Jura by de Loriol and others*. It was 

 originally described and figured by Quenstedt in the ' Jura ' as 

 Solanocrinus asper, its surface being roughened by fine tubercles. 

 The same writer has again figured his original specimen in his 

 ' Encriniden,' giving a different view of it from that represented 

 in his earlier figure. No external basals are present in the latter, 

 and there is no mention of them in the accompanying descriptions. 

 But in the later figure fairly large basals are represented, while 

 Quenstedt also describes and illustrates a tetraradiate form with 

 Jive basals, so that they may be regarded as characteristic of the 

 type. Figures 19 a, b, c on PL XI. represent three views of a 

 small specimen from Streitberg (White Jura, a), in the Miinster 

 collection of the Woodwardian Museum, that appears to be iden- 

 tical with Quenstedt's species. The centrodorsal is a pentagonal 

 disk with its angles produced into five strong ribs, each of which 

 is marked by a distiuct groove. The grooves start from near the 



* The literature of this speoies may be found on p. 257 of de Loriol's ' Cri* 

 no'ides Fossiles de la Suisse,' part iii. (1879), 



