456 On Specimens dredged up from the Gulf of Manaar. 



stolon (magnified 2 diameters), a, calycle, with portion of 

 stolon cut oft' to show the vertically compressed form of the 

 latter and cavity respectively ; b, vertical section of stolon ; 

 c, compressed cavity ; d, lateral view of tentaculated head when 

 restored to position (ideal) ; e, end view of same sunk into 

 the calycle: all relatively magnified on the scale of l-144th 

 to l-1800th inch. /, form of young spicule ; g, matured form 

 (diagrams), h, fragment of the corallum, to show pore-openings 

 between the calcareous tubipora-spicules, now otherwise con- 

 solidated ; i } fragment of siliceous sponge-spicule imbedded in 

 the same : scale l-48th to l-1800th inch, k, sponge -spicules 

 imbedded in the corallum at the bottom of the calycle, as seen 

 on looking down through the end of the latter (diagram). 



Fig. 3. Polytrcma mesentericum, n. sp., nat. size of specimen, a, por- 

 tion of mesenteriform lamina, to show — b, pore-surface on the 

 sides and, c, cortical and medullary cell-structure in the hori- 

 zontal section : magnified 2 diameters, d, horizontal section of 

 fragment, more magnified, to show — e e, pore-tubules, ff, cor- 

 tical cells, and g, medullary cell-structure; li, fragment of surface, 

 to show pore-openings (diagrams). 



Fig. 4. Holocladina pustidifera, n. sp., suspended across a crevice in the 

 Melobesian nodule, into which the ends of the branches are for 

 the most part inserted, therefore represented as cut oft' (magni- 

 fied about 10 diameters), a, average natural size, b, end view 

 of large pustuliform eminence; c, the same, lateral view; d, the 

 same, with summit extended into a spinous form : scale l-24th 

 to l-1800th inch, e, eud of branchlet, much magnified, to 

 show the distribution and unequal size of the pustuliform 

 eminences, also /, the structure and thickness of the test, 

 g g, the conical, and h, the amorphous terminations respectively 

 (diagrams) . 



Fig. 5. Cysteodictyina compressa, n. sp., in contact with the surface of the 

 Melobesian nodule, represented as cut off at each end where the 

 continuation of the circumference was not seen (magnified 

 about 1(3 diameters), a, average natural size ; b, fragment of 

 surface, much magnified, to show the prismatic structure of the 

 pore-tubulation ; c, end of circumferential lobule, much magni- 

 fied, to show thinness of test and punctate surface, also d d, coni- 

 cal, and e e, amorphous terminations respectively (diagrams). 



Plate XIX. 



Fig. G. Ceratestina globtdaris, n. sp. a, embryonic or primary cell ; 

 b, terminal cell or chamber ; c, connecting stolon ; d d, crooked 

 and knotted stolonic tabulations put forth by the last chamber ; 

 e, microspiuous processes on the surface of the chamber ;/, groups 

 of Ceratestina on the surface of old Stylaster sanguineus from 

 the S. Pacific Ocean ; g, aperture of terminal cell : scale l-24th 

 to l-1800th inch. 



Fig. 7. Ceratestina tessellata, n. sp. a, globuliferous or adenoid portion ; 

 b, stolonic tubes : magnified about 16 diameters, c, commence- 

 ment of the growth of a globuliferous portion on a stolonic 

 tube ; d, globuliferous portion, much magnified, to show nieri- 

 dionate or crossing lines of fibre in the horny wall, producing 

 the tessellated appearance ; e, stolonic portion ; f, internal pro- 

 cesses ; g, end of stolon, more magnified, to show that it also 



