Mr. II. .1. Carter on two Hexactinellid Sponges. 127 



fusiform, attenuately pointed), unspined, but uneven on the 

 surface and hero and there microsj)ined ; lenj^jth unknown ; 

 hirgest fragment 170- by J-lSOOth incli in it.s [greatest 

 diameters (iig. 17). Flesh-spicules of two forms, vi/. : — 1, 

 rosette, globular, consisting of six short arms (tlie third axis, 

 which is vertical to the other two, is omitted in the illustration 

 for perspicuity), each of which is surmounted by five long 

 capitate rays expanded in a vasiform manner, 4 i-l800ths inch 

 in diameter (fig. 14 and fig. 10, /) ; 2, bundles of miimtc, 

 hair-like, undulating aeorates like; the tricurvatti or Ijow spi- 

 cule, about 4-1800ths inch long (fig. 15 and iig. 10, ,</). 



The small scxradiates become the centres respectively of 

 the trapezoids (fig. 9, c), which are thus formed by the exten- 

 sion of a thread of vitreous sarcode from one end of each ot 

 the arms of the sexradiate spicule to the other (fig. 9, a), 

 strengthened at each attachment by subsidiary threads, which 

 form an irregular reticulation between the main thread and the 

 arm at each end of the latter (fig. 9, />) ; finally increasing in 

 thickness throughout till the trapezoidis fully formedand presents 

 four sides (fig. 10, a), with eight lantern-like holes in them, one 

 in each triangular face (fig. 10, i), through which the sexradiate 

 form of the original spicule may be seen in the centre intact 

 (fig. 10, c). Trapezoid about 14-1800ths inch in diameter. 

 Spicules nos. 2 and 3 form the fringe round the apertures 

 which interknits with the body-structure of the lamina in- 

 ternally, the latter, or the supposed acerate form, extending 

 beyond the former, both distally and proximally ; while the 

 flesh-spicules are scatteredthroughoutthe structure unequally — 

 that is, much more numerously towards the surface. Size ^ 

 inch high by -;- inch in horizontal diameter. 



Ilab. Marine, 



Loc. Island of St. Vincent, West Indies. 



Obs. In the Proc. Zool. Soc. Lond. 1859, p. 439, pi. xvi. 

 Radiata, the late Dr. J. E. Gray described and illustrated a 

 vitreohcxactinellid sponge, to which he gave the name of "3/y- 

 liusi'a calloci/athcsj'^ after Christopher Mylius of 1753. There 

 are two specimens of this sponge in the British Museum, viz. 

 the original one (figured /. c), about 3| inches in diameter, and 

 the other about H inch wide, numbered "43.2.13.67." Both 

 are stated by Dr. Gray, in his " Notes on the Arrangement 

 of Sponges " {op. cit. 1867, p. 506), to have come from the 

 West Inflies. To which a third specimen has been added from 

 the " Island of St. Vincent in the West Indies, collected by 

 the Rev. L. Guilding," with the name " Scriviner " (? dealer) 

 on the board bearing the specimen, numbered "40.10.23.11." 



In the same * Proceedings,' but of 1869 (p. 335, pi. xxv. 



