MR. J. W. GREGORY OX ARCH^OPNEFSTES ABRTJPTFS. 167 



The absorption of Ps;eudasterostoma and the removal of M. Cot- 

 teau's two species to the adete Spatanf/idce deprive the Plesiospa- 

 tangidce of the most important h'nks between the two orders (Spatan- 

 goidea and Cassiduloidea), but leave it as a more homogeneous group, 

 though bereft of the particular interest that Duncan had assigned 

 to it. 



The following synonymic summary of the genera in question may 

 render the above conclusions less liable to be misunderstood. 



Asterostoxna, L. Agassiz, 1847, Ann. Sci. Nat., Zool. 

 ser. 3, t. vii. p. 168. 

 T excentricum, L. Agassiz, ojj. cit. p. 168. 



cubense^ Cotteau, = Archceopneustes. 

 Jimenoi, Cotteau, = Palceopneustes. 

 Palseopneustes, A. Agassiz, 1873, Bull. Mus. Comp. Zool. 

 vol. iii. no. 8, p. 188. (First diagnosed by P. M. 

 Duncan. Journ. Linn. Soc.-, Zool. vol. xxiii., 1890, 

 pp. 223, 224. 

 T cristatus, A. Agassiz, 1873, Bull. Mus. Comp. Zool. 



vol. iii. no. 8, p. 189. (Figd 111. Cat. Mus. Comp. 

 Zool. no. viii. p. 14, pi. iv. figs. ]-3 ; also Mem. 

 Mus. Comp. Zool. vol. x. no. 1, pp. 58-60, pi. xxi.) 

 Jixnenoi (Cotteau). 



Sju. Asterostoma Jimenoi, Cotteau, 1871, Mem. Soc. geol. 

 France, ser. 2, t. ix. pp. 180, 181, pi. xvi, fig. 1, 

 pi. xvii. fig. 1. Also Ann. Soc. geol. Beige, t. ix. 

 1882, Mem. pp. 25-27. 

 Fseudasterostoma Jimenoi (Ootteau). P. M. Duncan, 

 1890. Eevision, Journ. Linn. Soc, Zool. vol. xxiii. 

 pp. 203, 204. 

 conicus^ Dames, 1 877, Palseontographica, vol. xxv. p. 47, 

 pi. viii. fig. 1, = Plesiolamjms. (See Duncan, op. 

 cit. pp. 194 & 224.) 

 Murrayi^ A. Agassiz, 1879, Proc. Amer. Acad. vol. xiv. 



p. 210, = Lmopneustes. 

 Antillarwn (Cotteau), Duncan, op. cit. p. 224, = Peri- 

 pneustes. 

 ArchseopneusteS) n. gen. 

 T hystrix (A. Agassizj. 



Syn. Palceopneustes hystrix, A. Agassiz, 1880. Bull. Mus. 

 Comp. Zool. vol. viii. no. 2, p. 82. (Fig** ' Blake ' 

 Echini, Mem. Mus. Comp. Zool. vol. x. no. 1, 

 pp. 58-60, pis. xviii , xix. fig. 2.) 

 cubensis (Cotteau). 



Syn. Asterosto7na cuhense, Cotteau, 1871. Mem, Soc. geol. 

 France, ser. 2, t. ix. pp. 181, 182, pi. xvi. figs. 2-4, 

 pi. xvii. figs. 2-4. Also Ann. Soc. geol. Beige, ix. 

 1882, Mem. pp. 27-30. 

 abruptus, n. sp. 



Q. J. G. S. No. 190. 



