Mr. H. J. Carter on Sponges. 27 



&c.) ; </, the fourth arm, which is curved towm-ds the orifice of 

 the cloaca in situ, and often joins the straight arm at a little 

 distance from its union with the other two. 



Fig. 33. Cliona coraUinoides, Hancock (Ann. Nat. Hist.), portion of, after 

 having been dissolved out of the deciduous shell of Cardimn 

 edule, and dried ; magnified 2 diameters : a a, pore-heads ; 

 h, vent. 



Fig. 34. The same, pore-head in the midst of a thalloid expansion of 

 Melohesia lichenoides, beneath which the sponge had grown ; 

 taken fi-om a dry-mounted specimen ; magnified, on the scale of 

 1-48 to l-1800th of an inch ; natural size about l-24th of an 

 inch in diameter : a an, border of the pore-area ; bhb, tentacle- 

 like prolongations of the sponge-structure, bristling, in the 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 exception of the pore-openings, d. 



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

 commimicating with each other : aaa, border of area ; hbh, ten- 

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

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

 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 figui'e for con- 

 venience. 



Fig. 36. 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 efierent apertures, e c c, in the areolar cavi- 

 ties, a a; b, pore-head. 



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

 scale of l-24th to l-6000th of an inch : a, pin-like spicule 

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

 areolar structure; c, minute tortuous spined spicules of the 

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



Fig. 38. Clion a celata-. ampullaceous 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 coinjn-essa in fig. 29, which are magnified to 

 the same scale, viz. l-12th to l-6000th of an inch. 



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

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



Fig. 40. Leueonia Johnstonii. C/nciliated mouth of cloaca, much magni- 

 fied, to show arrangement of the arms of the great quadriradiate 

 spicules of the surface : a, vent ; bbb, quadriradiate spicules ; 

 c c, their fourth arm projecting into the cloaca. 



Fig. 41. Botryllus pohjcyclus. Fragment of gelatinous mass showing a 

 group of Ascidians, magnified ; arranged round a common 

 cloaca : a, integument ; b, Ascidians ; c, branchial orifice ; d, anal 

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



Fig. 42. Bell-shaped colourless infusorium, common on Cladophm'a in 

 the freshwater tanks of Bombay. Cell about l-7466th 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 vnth Prof. James- 

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



