620 ME J. W. GREGORY ON THE MALTESE FOSSIL ECHINOIDEA. 



Species 3. Brissus tuberculatus, Wright, 1864. 



" Foss. Echinidse Malta," Quart. Journ. Geol. Soc, xx. pp. 486, 487, pi. xxii. f. 1. 



Type.— Brit Mus., E. 1866. 



Distribution. — Malta — Upper Coralline Limestone. 



Species 4. Brissus oblongUS, Wright, 1855. 

 Synonymy — 



Brissus oblongus, T. Wright, 1855, "Foss. Echinod. Malta," Ann. Mag. Nat. Hist. (2), xv. pp. 

 184, 185, pi. v. f. 2. 

 „ cylindricus ? E. Desor, 1858, Syn. itch, foss., p. 404. 

 „ „ T. Wright, 1864, "Foss. Echinidce Malta," Quart. Journ. Geol. Soc, xx. p. 485. 



Type.— Brit. Mus., E. 1562. 



Distribution. — Malta — Upper Coralline Limestone and Globigerina Limestone (?). 



Remarks. — Desoe suggested that this species might be the same as B. cylindricus, 

 Ag. ; but the original diagnosis of this species lays stress upon its resemblance to B. col- 

 umbarius (Lam.),* [i.e., B. unicolor, Leske), from which this species is very different. 

 Nevertheless Dr Weight, in his later work on the Maltese Echinoidea, accepted the 

 suggestion unreservedly, and abandoned his species. But as an examination of some 

 Brissi from the Palermo Pliocenes has led me to place B. cylindricus as a synonym of 

 B. unicolor,\ it is necessary to resuscitate Dr Weight's species. 



The type specimen has been so thoroughly scraped that no trace of tubercles or 

 fascioles remains ; nevertheless the species is well marked. On the evidence of some 

 imperfect specimens of an allied species, Dr Weight recorded B. cylindricus from the 

 Lower Limestone. These, however, seem to differ from the typical form in the more 

 anterior position of the mouth. Mr Cooke's collection includes a very typical specimen 

 from the lower horizon of the Upper Limestone at Entahleb. 



Species 5. Brissus depressus, n. sp. Plate II. fig. 2. 



Diagnosis. — Form depressed, elliptical ; anterior margin thin. 



Apical system not very excentric anteriorly ; four genital pores. 



Antero-lateral ambulacra very divergent, almost in a straight line ; in broad but 

 shallow depressions. Postero-lateral ambulacra are narrower and more depressed, and 

 curve outwards at the end, though the general direction is backward, close to the keel of 

 the posterior interradius. The anterior ambulacrum is very narrow, slightly raised, and 

 with very small pores. 



Interradii : The antero-lateral pair are very wide up to the apical system ; the 

 posterior interradius is narrow and keeled. 



* Lamarck, Anim. sans Vert., iii., 1816, p. 30. 



t " Revision of the British Fossil Cainozoic Echinoidea " Proc. Geol. Ass., xii., 1891, p. 41. 



