21. Egg of _Platygaster_, more advanced. 22. Egg of _Platygaster_, showing the rudiment of the embryo. 23. Larva of _Platygaster_.—_mo_, mouth; _a_, antenna; _kf_, hooked feet; _r_, toothed process; _lfg_, lateral process; _f_, branches of the tail. 24. Larva of another species of _Platygaster_. (The letters indicate the same parts as in the preceding figure.) 25. Larva of a third species of _Platygaster_. (The letters indicate the same parts as in the preceding figure.) 26. Larva of _Platygaster_ in the second stage.—_mo_, mouth; _slkf_, œsophagus; _gsae_, supra-œsophagal ganglion; _lm_, muscles; _bsm_, nervous system; _gagh_, rudiments of the reproductive glands. 27. Larva of _Platygaster_ in the third stage.—_mo_, mouth; _ma_, mandibles; _gsae_, supra-œsophagal ganglion; _slk_, œsophagus; _ag_, ducts of the salivary glands; _bnm_, ventral nervous system; _sp_, salivary glands; _msl_, stomach; _im_, imaginal discs; _tr_, tracheæ; _fk_, fatty tissue; _ed_, intestine; _ga_, rudiments of reproductive organs; _ew_, wider portion of intestine; _ao_, posterior opening. 28. Embryo of _Polynema_. 29. Larva of _Polynema_.—_asch_, rudiments of the antennæ; _flsch_, of the wings; _bsch_, of the legs; _vfg_, lateral projections; _gsch_, rudiments of the ovipositor; _fk_, fatty tissue. 30. Egg of _Phryganea_ (Mystacides).—_A_¹, mandibular segment; _C_¹-_C_⁵, maxillary, labial, and three thoracic segments; _D_, abdomen. 31. Egg of _Phryganea_ somewhat more advanced.—_b_, mandibles; _c_, maxillæ; _cfs_, rudiments of the three pairs of legs. 32. Egg of _Pholcus opilionides_, showing the Protozonites. 33. Embryo of _Julus_. 34. Colony of _Bougainvillea fruticosa_, natural size, attached to the underside of a piece of floating timber. 35. Portion of the same, more magnified. 36. The Medusa from the same species. 37. Larva of Prawn, Nauplius stage. 38. Larva of Prawn, more advanced, Zoëa stage. 39. Larva of Echino-cidaris œquituberculata seen from above × 6/10. 40. Larva of _Echinus_ × 100.—_A_, front arm; _F_, arms of the mouth-process; _B_, posterior side arm; _E_¹, accessory arm of the mouth-process; _a_, mouth; _a_¹, œsophagus; _b_, stomach; _b_¹, intestine; _o_, posterior orifice; _d_, ciliated bands; _f_, ciliated epaulets; _c_, disc of future _Echinus_. 41. _Comatula rosacea_. 42. Larva of _Comatula rosacea_. 43. Larva of _Comatula rosacea_, more advanced. 44. Larva of _Comatula rosacea_, in the Pentacrinus state. 45. Larva of Starfish (Bipinnaria), × 100. 46. Larva of Starfish (Bipinnaria), × 100, seen from the side.—_a_, mouth; _b_, œsophagus; _c_, stomach; _c_¹, intestine.