Report on the scientific results of the voyage of Challenger during the years 1873-76 : under the command of Captain George S Nares, , and Captain Frank Turle Thomson, . nHyalonema lusitanicum. The feathered shafts of the five-rayed sj^icules which fringethe openings are longer than in the other species, and the rays of the cross are muchshorter (fig. 7). The second specimen of the sponge body agreed with the one described in all EEPOKT ON THE HEXACTINELLIDA. 203 essential points of structure, but was more conical in form. The young specimendiffered from the young of Ilyal
Report on the scientific results of the voyage of Challenger during the years 1873-76 : under the command of Captain George S Nares, , and Captain Frank Turle Thomson, . nHyalonema lusitanicum. The feathered shafts of the five-rayed sj^icules which fringethe openings are longer than in the other species, and the rays of the cross are muchshorter (fig. 7). The second specimen of the sponge body agreed with the one described in all EEPOKT ON THE HEXACTINELLIDA. 203 essential points of structure, but was more conical in form. The young specimendiffered from the young of Ilyalonema lusitanicum at the same age in beingwider and more cylindrical, but the external wall, which afterwards becomes that of thelower surface, showed the same arrangement in squares which we find in the young ofthe other species, so that apparently the graceful, round-meshed, wide netting of theunder surface does not appear in the early stages. The coil is developed much in the same proportion and in the same way as inHyalonema lusitanicum, the filjres spreading out and incorporating with the spongesubstance. The characteristic bow-like spicules are abundant in the young sponge, and. Fig. 7.—Hyalonema toxeres, Wyville Thoinsou. Part of the membraue from the upper surface, x 40. these, with the larger amphidiscs, place it beyond a doulit that it is the young ofHyalonema toxeres. A quantity of loose spicules brought up in the dredge at the same time were referredto this species. They were somewhat stouter than those of Hyalonema lusitanicum, andless regular in outline. There was one coil nearly complete, involved in a calcareousexpansion of a branch of Diplolielia profunda. Two very young polyps, apj)arently ofPalythoa fatua, were commencing the formation of theii- investing crust at the top ofthe coil of the young specimen, just below the sponge body. Since the three specimens studied by Wyville Thomson are also at my disposal for 204 THE VOYAGE OF CHALLENGER. examinat
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectscienti, bookyear1887
