OCR Text |
Show 1869.] DR. J. S. BOWERBANK ON SILICEO-FIBROUS SPONGES. 99 Fig. 10. A dichotomo-patento-ternate connecting spiculum from the type spe- - cimen, magnified 10£ linear. Fig. 11. Minute attenuato-stellate retentive and defensive spicula from the type specimen, magnified 666 linear. Fig. 12. A gemmule adhering to auxiliary fibres of the skeleton from the large specimen of D. pumiceus (Iphiteon panicea, Valenciennes) in the collection of the Jardin des Plantes, Paris, magnified 108 linear. Fig. 13. A profile view of two of the tubercles on the skeleton-fibre of the type specimen of D. pumiceus, exhibiting the papulation of their summits, magnified 666 linear. Figs. 14 & 15. Portions of the densely reticulated basal skeleton-structure from the type specimen, magnified 108 linear. Fig. 16. Trifurcated expando-ternate connecting spicula, probably belonging to an unknown species of Dactylocedyx, magnified 666 linear. PLATE IV. Fig. 1. A portion of the rigid skeleton of Dactylocalyx heteroformis (Goscino-spongia teeter of or mis, Valenciennes), exhibiting the complicated reticulations of the structure, and the ramified free terminations of the fibres, magnified 175 linear. Fig. 2. One of the large incurrent areas of the inhalant surface of the same sponge, exhibiting the protective furcated terminations of the marginal fibres, magnified 308 linear. Fig. 3. One of the oscula from the exhalant surface of the same sponge, exhibiting the oscular membrane in a half-open condition, magnified 183 linear. Fig. 4. A portion of the dermal membrane of D. heteroformis, with its fine but very irregular network of siliceous fibre, magnified 308 linear. Fig. 5. A portion of the dermal membrane of Dactylocalyx McAndrewii (MacAndrewia azorica, Gray), exhibiting the ramifications of the foliato-expando- ternate connecting spicula beneath, and one of the inhalant pores with its defensive system of minute acerate dermal spicula, magnified 183 linear. PLATE V. Fig. 1. A portion of the rigid skeleton of Dactylocalyx McAndrewii, magnified 175 linear. Fig. 2. A foliato-expando-ternate connecting spiculum from the expansile dermal system of D. McAndrewii, with the inner surface towards the eye exhibiting the short acutely conical shaft of the spiculum, magnified 175 linear. Fig. 3. A n elongated and more ramose variety of the ternate head of the same sort of spiculum as that represented by fig. 2, magnified 175 linear. Fig. 4. A view in profile of a spiculum of the same form as those that are represented by figs. 2 & 3, magnified 175 linear. Fig. 5. One of the minute fusiformi-acerate tension-spicula of the dermal membrane of D. McAndrewii, magnified 666 linear. Fig. 6. A section at right angles to the surface of D. Prattii, exhibiting a portion of the expansile system (a) in a state of separation from the rigid siliceo-fibrous skeleton beneath, with the shafts of the connecting spicula pendent in the space between them, and also the primary dermal membrane, and the secondary membrane covering the external surface of the rigid skeleton filled with the innumerable retentive spicula of those organs, magnified 108 linear. Fig. 7. Two of the retentive spicula of the dermal membrane and the investing membrane of the rigid skeleton, magnified 1250 linear. Fig. 8. A view of the inner surface of a portion of the expansile dermal system, exhibiting the interlacing of the radii of the irregularly furcated patento-ternate connecting spicula to form the inhalant areas, in which are situated the pores of imbibition, magnified 108 linear. Fi°*s 9,10, & 11. Three of the irregularly furcated patento-ternate connecting spicula, exhibiting their extreme diversity of form, magnified 108 linear. |