61 



size and arrangement from the corresponding spicules of other species of 

 Euplectella, particularly Euplectella simplex, described above (pi. XI, f. 4). 



The same can be said of the parenchymal graphiocoms, which also here occur 

 irregularly scattered, but always vertical to the surface, not very frequently in the 

 external region of the body, in the vicinity of the dermal membrane (pi. XI, f. 4). 



On the other hand the parenchymal oxyhexasters, absent in ErqylectelJa simplex, 

 are present in E. aspera and are here pretty uniformly distributed throughout 

 the parenchyme. They measure 120 /^ in diameter, are characterised by the 

 remarkable tenderness of their main- and branch-rays, and generally bear three 

 or four quite smooth and slightly curved branch-rays on each main-ray (pi. 

 XI, f. 8). 



The floricoms, one of which is attached to the distal ray of each sword- 

 shaped hypodermal, measure 120 m in diameter. Each one of their short main- 

 rays bears 8-12 branch-rays so arranged as together to represent a flower-calyx. 

 The terminal discs of the bi-anch-rays are convex and bear on their outer, free, 

 semicircular, sharp margin a considerable number (about twelve) of small pointed 

 teeth (pi. XI, f. 9). Among these normally developed floricoms with thick 

 terminal discs, sometimes also floricoms are met with the branch-rays of which 

 are much thinner and do not bear a nearly hemispherical end-plate, but terminate 

 with slightly club-shaped thickenings, without discs or marginal teeth (pi. XI, 

 f. 10). I am not inclined to consider these spicules as a special kind of floricom, 

 but suppose them to be young stages of the ordinary floricoms above described. 

 This view is supported by the fact that there exist transitional forms connect- 

 ing these disc-less floricoms, the branch-rays of which are simply pointed, with 

 the disc-bearmg floricoms of the usual form represented in fig. 9 ; and that the 

 few disc-less floricoms do not differ in size, distribution or position from ordinary 

 floricoms. 



Only two specimens of this species are known. The smaller one, represent- 

 ed in figs. 1 and 2 on plate XI in natural size, was found in the most southerly 

 part of the Bay of Bengal 60' 18' N. 90° 40' E. in a depth of 2506-2816 m.= 

 1370-1540 fths. The larger specimen, represented in fig. 3 on plate XI, was 

 found in the Laccadives 11" 12' 47" X. 74° 25' 30" E. in a depth of 1830 m.= 

 1000 fths. 



Eup)Iectella regalis F. E. Sch. 

 Plate XXII, figs. 1-9. 



1900 Euplectella regalis F. E. Sch. in Abh. Preuss. Ak. 1900 pp. 24-30, Taf. V!, figs. 1-9. 



There is in the "Investigator" collection a single specimen, fairly well 

 preserved in spirit, of a new species of Euplectella, allied to Ijima's Euplectella 



