IN THE LOWER TERTIARY STRATA OF NEW ZEALAND. 229 



basal rays very unequally divided, resulting eibher in a simple 

 slight furcation near their extremities or in a division iato three 

 conical rays, as in the preceding spicules. The summit is formed 

 by three simple, slightlj'- recurved rays on a short base. Height 

 of spicule '021 mm., width of base "025 mm. ; summit-rays, 

 length '006 mm., thickness "OOSS mm. In the simple character 

 of the summit-rays and inequal division of the basal rays, this 

 form agrees with the spicules of Corticium versatile, Osc. Sch. 

 (Mexican Spong. p. 69, pi. ix. fig. 5), from St. Vincent, at a depth 

 of 95 fathoms. 



Corticium (e). — PL XII. fig. 18. Candelabrum in which the 

 three basal rays are equal and simple, with an occasional spine 

 here and there ; the summit consists of three or four minute 

 pointed rays and one or two spines. Length of basal rays "031 

 mm. each, thickness "006 mm. This form also corresponds in 

 character with the spicules of C, versatile, Osc. Sch. 



Pi. XII. fig. 19. Candelabrum with simple, elongate, pointed 

 basal rays and a summit of about six divergent rays, which are 

 slightly bi- and trifurcate at their extremities. Length of basal 

 rays "OSG mm. each, thickness '0053 mm. ; summit-rays, length 

 "012 mm., thickness "0033 mm. In the terminal character of the 

 summit-rays this spicule resembles that represented by fig. 16. 



The number of tiie rays in the candelabra spicules of Cortvcium, 

 as remarked by Osc. Schmidt (Mexic. Spong. p. 69), varies in the 

 same species to such an extraordinary extent, according to the 

 degree of subdivision of the four normal rays of the typical 

 calthrops spicule, that it is not easy to determine the number of 

 species which these detached spicules may represent. But the 

 character of the summit-rays of the spicules gives a probable 

 clue, for whilst some are capped by small tubercles, others are 

 claw-shaped and pointed, and others, again, have furcate ends, 

 and each of these difierejit forms may belong to a separate species ; 

 and in this case three, if not four, species are present in the 

 Oamaru material. This genus is very sparsely represented iu 

 existing seas ; not more than three or four species are known, 

 and these are found in the Adriatic, off the coast of Algiers, 

 Zebu, and St. Vincent. Only a single detached spicule has 

 previously been discovered as fossil in Jurassic strata near 

 Cracow. 



