IN' THE LOWEE TERTIARY STRATA OF NEW ZEALAND. 207 



tubercle conical, slightly projecting below the base. Axial 

 canal extending from the upper to the lower tubercle. Length 

 of spicule -076 mm., of large end '046 mm., width of same 

 •038 mm. Length of small end of spicule "012 mm., width '02 mm. 

 Shaft -006 mm. thick. 



JEsj)erella (h). — PL X. fig. 13. Inequianchorate, large end 

 serai-elliptical ; large prominent pear-shaped tubercle, the upper 

 end projecting beyond the summit. Small end of spicule sub- 

 oblong; prominent ovate tubercle, base nearly straight. Length 

 of spicule '076 mm., of large end '04 mm., width -SO mm. 

 Length of small end "013 mm., wddth '023 mm. Thickness of 

 shaft "013 mm. This form differs from the preceding in the 

 thicker shaft and larger tubercles at the upper end. It corre- 

 sponds in form with the large inequianchorate figured by Ridley 

 in Esperia gelatinosa ('Alert ' Eep. p. 611, pi. liv. fig./"), from 

 near Providence Island, Mascarene Grroup. 



Esperella (i). — PI. X. fig. 14. Inequianchorate with semi- 

 ovate larger end, the lateral palms with evenly curved revert mar- 

 gins, projecting slightl}'' below and arched inferiorly. Tubercle 

 large, pear-shaped, anterior palm tongue-shaped. Small end 

 of spicule evenly rounded, central tubercle triangular ; anterior 

 palm extending across base, upper margin convex. Length of 

 spicule "086 mm., of larger end '053 mm., width "04 mm. Length 

 of small end "016 mm., width -023 mm., thickness of shaft 

 •0067 mm. 



Esperella (k). — PI. X. fig. 15. Inequianchorate with large 

 end subtriangular in outline ; lateral palms, margins curved, 

 slightly prolonged inferiorly ; lower end with rounded base. 

 Length of spicule '08 mm., of larger end "036, length of smaller 

 end '01, width '02. Only the lateral view of this spicule is 

 known. 



The foregoing spicules (PL X. figs. 3-6, 11-15) all exhibit 

 th.e same general characters as the large inequianchorates in 

 recent species of JEsperella, and they differ from these and from 

 each other only in minor details. It is probable ttat each form 

 represents a distinct species. 



Esjperella (1). — PL X. fig. 7. Small inequianchorate with 

 strongly curved shaft, the larger end with evenly rounded lateral 

 palms and very prominent anterior tubercle. Small end of 

 spicule subquadrate in outline, with an ovate subcentral tubercle. 

 Length of spicule "034 mm., of large end '022 mm., width 



