MR J. "W. GREGORY ON THE MALTESE FOSSIL ECHINOIDEA. 591 



Remarks. — This species appears to be confined to the upper beds,, and the type 

 specimen came from the white limestone at the base of the " Gozo Marble." The promi- 

 nence of the vertical row of primary tubercles down each side of the interradii gives 

 it a certain resemblance to Stirechinuss cilice, Desmoid, (see p. 627), but from this it is 

 quite distinct. This species may be readily distinguished from E. duciei, Wr., which 

 occurs on the same horizon, by the structure of the apical disc and the paucity of primary 

 tubercles. From E. tongrianus, to which it is allied by the former character, it may be 

 distinguished by the greater abundance of the tubercles. 



The differences in the distribution of the epistroma in the species may be thus 

 diagrammatically expressed (pi. I. f. 5d, 6, and 7cl). 



As this species seems to be the representative in the Tortonian of the E. tongri- 

 anus of the Lower Coralline Limestone, it is named after the horizon of which it is 

 characteristic. 



Species 3. Echinus tongrianus, n. sp. Plate I. fig. 7a-d. 



Diagnosis. — Test small, slightly pentagonal, tumid sides ; slightly conical. 

 Apical system small ; the antero-lateral basals are large, and push the anus backwards, 

 and exclude the anterior radials from the anal ring. The postero-lateral radials, however, 

 enter the ring. 



Ambulacra : The trigeminal arcs are considerably inclined from the vertical. Each 

 area is ornamented by a row of prominent tubercles, practically equal in size to those of 

 the interradii. Miliary granules few. 



Interradii : A pair of rows of tubercles down each area ; every primary tubercle is 

 surrounded by a scrobicular circle, composed of a crescentic arch, completed adorally by 

 the granules of the adjoining plate. The granules are few in number. 



Dimensions. — Diameter, 15 mm. ; height, 6 mm. ; width of ambulacra at ambitus, 

 3 mm. ; width of interradius at ambitus, 5 mm. 



Distribution. — Malta — Oligocene ; Scutella, bed of the Lower Coralline Limestone. 



Type.— Brit. Mus., E. 3403. 



Remarks. — This species may be readily distinguished from specimens of Echinus 

 duciei, Wr., by the structure of the apical system (cf. Weight, Ann. Mag. Nat. Hist. 

 (2), xv., pi. iv. f. 2, e), and by the fact that there is but one row of primary tubercles down 

 each side of the interradii. The species is most closely allied to Echinus biarritzensis 

 (Cott.) from the " Couches a Rotularia spirulsea"* (i.e., Bartonien) and the " Calcaire a 

 asteries" (Tongrian) of the S. of France. This latter species has, however, a secondary 

 tubercle on each interradial plate, and the pores are in a nearly vertical row. 



* " Echinides fossiles des Pyrenees," Congres scientifique de France, sess. xxviii. t. iii., Bordeaux, 1863, pp. 222, 223, 

 pi. I. f. 5-9. 



