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Show 134 ZOOLOGICAL COLLECTIONS M A D E DURING [Jan. 4, diately interior to these and similarly arranged, and a gastral of sagittal triradiates, the basal ray pointing away from the gastral surface, which is covered with quadriradiates. Body-acerates straight, tapering from centre to sharp points, external end flattened, knifelike, with a central thicker longitudinal ridge, minutely roughened ; size 1-25 by '06334 millim. Fine linear spicules of lip smooth, straight, size about '3 by '00475. Triradiates smooth, external ones irregular, angles about equal, all rays somewhat curved; rays respectively '1013 to '20 millim., '23 to '4, '32 to"45 in length by-019 to *022 in breadth; intermediate triradiates sagittal, angles equal or oral angle about 130°; basal ray '4624 by '03167 millim.; lateral rays curved, "2724 by '03167 millim.; gastral triradiates sagittal, oral angle 160°, proportions and shape of rays the same as of intermediate spicules. Quadriradiates, two sizes: (1) with characters of gastral triradiate but with small straight apical ray ; (2) smaller, lateral rays curved towards cloaca: sizes respectively, basal rays "38 by "03167 and-1267 by "0095 millim.; laterals "29 by "03167 and "1267 by •0095 millim.; apical "0565 by "01267 and "1267 by "0095 millim. Ratio of thickness of stoutest acerate to stoutest triradiate 2:1. Examined. In spirit and by sections in balsam. Hab. Victoria Bank (off S.E. Brazil), 39 fathoms; bottom, coral. Obs. One specimen represents this species; the mouth is not well preserved. It is covered in places with a brown coating of degenerate tissue. It belongs to the same group of the genus as N. {As-candra) echinoides, Hiickel, from Java, which it resembles in its flattened shape, and the form of the large acerate. But the largest triradiates are more than twice the size of those of that species, and two kinds of quadriradiate occur instead of one. APHROCERAS SERICATUM, sp. n. (Plate XI. fig. 5.) (Aphroceras, Gray, P.Z.S. 1858, p. 113; Leucandra, Hackel, Kalkschwamme, ii. p. 110.) Sponge tubular, elongate ; tube of almost equal diameter from the slightly fringed mouth to near the rounded basal end; length from 2 to 3 times as great as the maximum diameter. Canal-system and spiculation that of Leucandra, Hackel. Wall about 1 millim. thick, penetrated by long stout acerates measuring 2 to 3 millims. by 06 to '073 millim., smooth, sharply pointed, slightly thicker proximally, projecting from surface. Mouth fringed by a number of slender acerates about -014 millim. in diameter, smooth and straight. Internal triradiates sagittal, rays smooth, tapering to sharp points, slightly undulating, oral angle varying from 11 0° to 160°, lateral angles equal, basal ray measuring from "355 to "52 by -019 to "032, the laterals slightly smaller; external triradiates with aboral lateral generally only about half the length of the sagittal. Quadriradiates, rays smooth, gently curved and sharply pointed, facial rays each measuring from -18 to "25 by '0095 millim., apical ray from '16 to *2 by "0095 millim. Ratio of diameter of stout acerate to maximum diameter of rays of triradiate between 2 and 3:1, Colour (in spirit) white. |