Dr. J. W. Gregory — Egyptian EcJdnoidea. 153 



Eemarks. — This species is represented by three specimens. The 

 pores are in arcs of five to six pairs in each compound ambulacral 

 plate. The specimens agree with the Algerian type in all important 

 respects. The ambulacral plates are unituberculate, and each 

 tubercle is surrounded by a couiplete scrobicular circle, so that the 

 scrobicular areas are not confluent. The tuberculation of an 

 Egyptian specimen is shown on PL V, Fig. 2, 



Genus LAGANUM, Gray, 1825. 

 1. Laganum depressum, Less. 



S"SNONYMY. — See A. Agassiz, " Eevisioji of Echini," pt. i, 1872, 

 p. 138. 



DiSTKiBOTiON. — Recent : Pacific and Indian Oceans, Eed Sea, 

 Persian Gulf. Pleistocene : E. Africa ; Suez ; Coll. Geol. Surv. 

 Egypt, No. 968. 



Eemarks. — The collection includes six specimens of a Laganum 

 from the Pleistocene of the Suez Canal (Coll. Geol. Surv. Egypt, 

 No. 968). The specimens appear at first sight to differ from the 

 typical L. depressum, as the margins are tumid, and there is 

 a depression around the test between the apex and the margin. 

 This character is described by Professor A. Agassiz in L. Bonani,^ 

 whereas the test of L. depressum is said'^ to have thin margins. The 

 shape of the petals in one or two specimens is also different from 

 the typical L. depressum, as the petals are more pointed at their 

 outer ends. Examination, however, of the large series of L. de- 

 pressum in the Zoological Department shows that these characters 

 vary so much in this species that the Egyptian fossils may be safely 

 referred to it. Some specimens registered as 58. 5. 15. 154, have 

 equally pointed petals ; others from the Kingsraill Islands have the 

 petals pointed at the ends, but the poriferous zones are broader ; 

 while in some other specimens the pore-zones are as narrow as in 

 the fossil specimens from Suez. Among the many varieties of 

 L. depressum these specimens are most nearly allied to Laganum 

 attenuatum, L. Ag.,^ with which they agree in the circular actinal 

 depression and the general shape of the test. Some of the six 

 speciuiens have the external shape of the variety L. ellipticum, L. Ag.,* 

 and other's have the more strongly pentagonal shape of the typical 

 L. depressum.^ 



L. attenuatum is a variety most typical of the Red Sea and 

 Persian Gulf. 



Genus SCUTELLA, Lam., 1816. 

 1. ScuTELLA suBROTUNDA var. Paulensis, L. Ag.,^ 1841. 

 Remarks. — This echinid is represented in the collection by two 

 Miocene specimens (No. 995), of which one is broken. The 



1 A. Agassiz, Revision Echini, pt. iii (1873), p. 517. 



2 Ibid., p. 518. 



■'' L. Agassiz and Desor, " Cat. Eaiss." : Ann. Sci. nat., vol. vii (1847), p. 132. 



* L. Agassiz, Mon. Scut., p. Ill, pi. xxiii, figs. 13, 14. 



* Cf. ibid., pi. xxiii, figs. 1-3. 



® Hculella I'aulensis, L. Agassiz, Monogr. Scutelles, 1841, p. 83, pi. xix, figs. 8-10. 



