Mr. II. . I. Carter mj Sponger. 27 



Ac.) ; rf, the fourth arm, whicli is curAed toininU tho orifice of 

 the cloaca •/* situ, and often ioins tho straij,'ht ana at a little 

 dititance from it.-* unicni with uxv other two. 



Fii/. 3.3. Cliotia coralliiK-ides, Hancock (Ann. Nat. Hist.), portion of, after 

 having' U'en dissolved out of tho deciduous .«hell of Cardium 

 eilulr, luid dried; magiiitied 2 diameters: (4 «, pore-heads ; 

 b, vent. 



Fiff. 34. The name, pore-head in tho midst of a thalloid expansion of 

 Meliihfsia Uchetioides, beneath which tho sponpe had prown ; 

 taken from a dry-mounted specimen; mapnititMl, on tho scale of 

 1-4?' to l-1^00th of an inch; natural .<ize about l-24tli of an 

 inch in diameter : a a a, border uf the pore-area; hbh, tentacle- 

 like prolnnjrations of the sponpe-structure, bristliup, in tiie dried 

 state, with the pointed ends of the pin-like spicules, and united 

 together by the dermal sarcode, c, which fills up all the inter- 

 stices, with the e.xception of the pore-opeuinps, a. 



Fig. 35. The same, pore-area with vent in the centre, combined, but not 

 communicating with each other : a a a, border of area : bbb, ten- 

 tacle-like prolongations of the sponge-structure, bristling, in the 

 dried state, with the ends of tne pin-like spicules, and united 

 together by the dermal sarcode, c, which fills up all the inter- 

 stices but the pore-openings, d, and the vent, e ; f, the pin-like 

 spicules, which are omitted in the foregoing figure ior con- 

 venience. 



Fig. 30. The same, diagram of vertical section of the pore-head and a 

 portion of the areolar structure of the body, magnified, to show 

 the absence of the excretory canal-system, whose function is 

 supplied by the large efi'erent apertures, c c c, in the ai'eolar cavi- 

 ties, a a ; 6, pore-head. 



Fig. 37. The same ; all the different spicules relatively magnified, on the 

 scale of l-24th to l-tJOOOth of an inch : a, pin-like spicule 

 of the pore-head ; b, spinous curved acerate spicule of the 

 areolar structure ; c, mmute tortuous spined spicules of the 

 pore-area ; d, the same, more magnified. 



Fig. 38. Cliotia celata ; ampullaoeous sac of sponge-ceUs, showing the 

 cilia vibrating internally ("' Wimperkorb '' of Schmidt) ; show- 

 ing also the relative size of the sponge-cells compared with 

 those of Grantia cotnpressa in fig. 29, which are magnified to 

 the same scale, viz. l-12th to 1-OOOOth of an inch. 



Fig. 39. The same, reproductive or ovi-cell, to show its relative size 

 when compared with the sponge-cells in fig. 38 : a, nucleus. 



Fig. 40. Lettcutiia Johnstonii. f 'jiciliated mouth of cloaca, much magni- 

 fied, to show arrangement of the arms of the gi'eat quadriradiate 

 spicules of the surface : «, vent \ bbb, quadriradiate spicules j 

 c c, their fourth arm projecting into the cloaca. 



Fig. 41. Botnjllus poJycijclus. Fragment of gelatinous mass shownng a 

 group of Ascidians, magnified ; arranged round a common 

 cloaca : a, integimient ; 6, Ascidians ; c, branchial orifice ; d, anal 

 orifice ; e, common cloacal chamber ; /, its vent. 



Fig. 42. Bell-shaped colourless infusorium, common on CJadophora in 

 the freshwater tanks of Bombay. Cell about l-746Gth of an 

 inch in diameter; total length about l-1600th of an inch. 

 Sessile, separate, in groups. Copied from a drawing in my 

 journal, made in March 1857 ; to compare with Prof. James- 

 Clark's figures of Salpingoeca amphoridium (I. c. pi. 9. fig. 37). 



