MR J. W. GREGORY ON THE MALTESE FOSSIL ECHINOIDEA. 595 



Clypeaster alticostatus, G. Seguenza, 1879, op. cit, Mem. R. Ac. Lincei (3), vi. p. 87. 



„ „ G. Bukowski, 1889, "Geol. Bau I. Kasos," Sitz. k. Ak. Wiss. Wien, xcviii. 



Ab. i. p. 664. 

 ,, agassizi, E. Sismonda, 1844, " Ech. foss. Nizza," Mem. R. Ac. Set. Torino (2), vi. 



pp. 388, 389, pi. ii. f. 5-7. 

 „ insignis, G. Seguenza, 1879, op. cit, Mem. R. Ac. Lincei (3), vi. p. 87, pi. ix. 



f. 2 a, c, d. 

 „ „ var. acuminatus, 1879, op. cit, Mem. R. Ac. Lincei (3), vi. p. 87, pi. iv. f. 2, 26. 



Type.— 56, Q. 17. 



Distribution. — Malta — Greensand (common), Upper Coralline Limestone ; Dingli, 

 La Binjemma, Ghain Toffika. Corsica — Santa Manza, Aleria, &c. France — Dax, 

 Bordeaux, &c. Austria — Eisenstadt (Leitliakalk), Raubstallbrunn (2nd Mediteran.-Stufe). 

 Italy — Nice, Superga (near Turin), San Miniato, Reggio, &c. (Helvetian), Dego (?). 

 Sardinia ; Sicily ; Kasos ; Asia Minor ; Crete ; Madeira ; Cordova ; Oran. 



Remarks. — Clypeaster alius was originally figured by Scilla,* but he gave no 

 adequate description, and simply referred to it as one " in nonnullis aliis echinis petre- 

 factis." The species was first named binomially by Leske, but as his figure is less 

 satisfactory than that of Scilla, reference is usually made to the earlier one. Thanks to 

 the clearness of this, there has been but little confusion as to the main type ; but as the 

 species is a very variable one, many names have been given to forms which seem to be 

 best included within it. Several of the best marked of these varieties occur at Malta. 

 Desor, in the Catalogue raisonne, briefly diagnosed a species from Taurus and Crete 

 as C. tauricus. From this description Weight identified as such a thick pentagonal 

 form from Malta. Having had the opportunity of examining this specimen, through the 

 kindness of the Earl of Ducie, in whose collection it now is, I have no hesitation in 

 regarding it as only a massive variety of C. altus. There is another specimen in the 

 collection of the Geological Society, labelled C. tauricus, by Dr Wright ; but this lacks 

 the great tumidity of the anterior margin, which seems to be the most important charac- 

 teristic shown in Michelin's fine figure of C. tauricus ; and this feature is probably only 

 due to the great size of the type specimen. 



Far more unlike the typical form are those described as C. portentosus, Desml., 

 C. pyramidalis (Risso), and C. turritus, Ag. ; but these all possess the same funda- 

 mental characters, and M. Cotteau has readvanced the view of their specific identity, 

 suggested by Agassiz and Desor in 1847. A collection in the Museum of Practical 

 Geology contains a fine series of these forms, and a gradual transition between the 

 extreme types can here be traced. C. alticostatus, it seems to me, must necessarily 

 follow, though M. Cotteau has retained it as distinct. The great thickness of the whole 

 test and the prominence of the ambulacral areas seem to be variations correlative with 

 increase in height. 



The var. portentosus is common at Malta ; there are several specimens in the Museum 



* Be Corporibus Marinis Lapid., eft. 2, pi. ix. f. 1, 2. 



