EXl'LANATIONS OF THE PLATES. XIX 



PLATE XIX. (p. 526). 

 various forms of radiolaria (after Haeckel). 



Pig. 1. Ethmosphcera sipJionophora. 



2. Actinomma inerme. 



3. Acanthometra xiphicantha. 



4. Arachnosphcera oligacantha. 



5. Cladococcus viminalis. 



PLATE XX. (p. 540). 

 campanularia gelatinosa (after Van Beneden). 



A, Upper part of the Stem and Branches, of the natural size. 



B, Small portion enlarged, showing the structure of the animal ; 

 a, terminal branch bearing Polypes ; b, polype-bud partially developed ; 

 c, horny cell containing the expanded polype d ; e, Ovarian capsule, con- 

 taining Medusiform gemmae in various stages of development ; /, fleshy 

 substance extending through the stem and branches, and connecting the 

 different polype-cells and ovarian capsules ; g, annular constrictions at 

 the base of the branches. 



PLATE XXI. (p. 575). 



PENTACRINOID LARVA OF ANTEDON (Original). 



Fig. 1. Skeleton of early Larva, as seen under Black-ground Illumina- 

 tion, showing its component plates : — b, 6, Basals, articulated below to 

 the highest point of the stem ; r 1 , r 1 , First Radials, between two of which 

 is seen the single Anal plate, a ; r 2 , Second Radials ; ?<*, Third Radials, 

 giving off the bifurcating Arms at their summit ; o, o, Orals. 



2, 3. Back and front views of a more advanced Larva, as seen by Inci- 

 dent Light, one of the pair of Arms being cut away in Fig. 3, in order 

 to bring the Mouth and its surrounding parts into view : — b, b, Basals ; 

 r 1 , r 2 , r 3 , First, Second, and Third Radials ; a, Anal, now carried upwards 

 by the projection of the Vent v ; o, o, Orals ; civ, Dorsal Cirrhi, developed 

 from the highest joint of the Stem. 



PLATE XXII. (p. 578). 

 structure of laguncula repens (after Van Beneden). 



a, Polypide expanded ; b, Polypide retracted ; c, another view of the 

 same, with the Visceral apparatus in outline, that the manner in which 

 it is doubled on itself, with the Tentacular crown and Muscular system, 

 may be more distinctly seen : — a, a, tentacula ; 6, pharynx ; c, pharyn- 

 geal valve ; d, oesophagus ; e, stomach ; /, its pyloric orifice ; g, cilia on 

 its inner surface ; h, biliary follicles lodged in its wall ; i, intestine ; 

 I; particles of excrementitious matter ; I, anal orifice ; m, testis ; n, ovary ; 

 o, ova lying loose in the perivisceral cavity ; p, outlet for their discharge ; 

 q, spermatozoa in the perivisceral cavity ; r, s, t, u, v, w, x, muscles. 



d, Portion of the Lophophore more enlarged: — a, a, tentacula; b, b, 

 their internal canals ; c, their muscles ; d, lophophore ; e, its retractor 

 muscles. 



PLATE XXIII. (p. 632). 



STRUCTURE AND DEVELOPMENT OF TOMOPTERIS ONISCIFORMIS (Original). 



a. Portion of Caudal prolongation, containing the Spermatic sacs, a, a. 



b. Adult Male specimen. 



