Lectures on the comparative anatomy and physiology of the invertebrate animals : delivered at the Royal College of Surgeons . ovicapsules. Thegerm-cell is thus suppliedwith matter for its growth,which proceeds rapidly bythe ordinary mode of multi-plication of secondary germ-cells by spontaneous growth proceeds the ovi-capsule expands, and the endof the nutrient diverticulumbecomes surrounded by thegerm-mass, into the middleof which the diverticulumseems now to dip, as shown Development of Tubularia coronata. -j^ g, fg. 62. The nCXt change is the development of a series of lobes whic
Lectures on the comparative anatomy and physiology of the invertebrate animals : delivered at the Royal College of Surgeons . ovicapsules. Thegerm-cell is thus suppliedwith matter for its growth,which proceeds rapidly bythe ordinary mode of multi-plication of secondary germ-cells by spontaneous growth proceeds the ovi-capsule expands, and the endof the nutrient diverticulumbecomes surrounded by thegerm-mass, into the middleof which the diverticulumseems now to dip, as shown Development of Tubularia coronata. -j^ g, fg. 62. The nCXt change is the development of a series of lobes which push aside thediverticulum, as in 3: the lobes elongate into rudimentary tentacles,and the base of the inner series of tentacles begins to appear, as atb, 4 : this stage is better seen when the ovisac is viewed under pres-sure as at 5. Where development has advanced thus far, the parietesof the ovicapsule rupture and the embryo escapes, as a young polype,with one series of tentacles, 6. It then becomes fixed, and beginsto develope its tubular body and its inner series of tentacles as in 7,Jig. G2. * CXI. p. 37. pi. POLYPI. 129 In a third species of Tubularia {T. Dumortieri) the embryoassumes the form of a transparent, gelatinous, longitudinally ribbedBeroe, before it escapes : and afterwards moves like a INledusa by-alternate contraction and expansion of the body. The change ofthis medusoid larva into the Tubularia was not seen. In the Hydraetinia rosea V. Beneden found several ova, withthe germinal vesicle and nucleus, developed in each ovicapsule. The modification in the growth of the coralline to form the ovi-capsule, has been compared by Professor E. Forbes* with that -me-tamorphosis in flowering plants in which the floral bud is constitutedthrough the contraction of the axis and the whorling of the indivi-duals borne on that axis, and by their transformation into the severalparts of the flower. Many elegant varieties are observable in theform of the ovicapsules. Some
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