Development of the notochord, pronephros, and cells of the CNS. Embryos of E. randi are shown in A and B, and embryos of of E. coloradorum are shown in C and D. (A) Expression of Lim1 in the notochord and anterior domain of a late gastrula. (B) Expression of Lim1 in the pronephros anlage and in cells of the CNS of a neurula. (C) Expression of myosin in the somites of a tailbud embryo. (D) Longitudinal section through the notochord and somites of a tailbud embryo, stained for cell nuclei. Embryos of C. machalilla are shown in E–H. (E) Expression of Lim1 in the notochord and precordal plate of a postgastrula. (F) Expression of Lim1 in the pronephros of a tailbud embryo. (G) Expression of Lim1 in cells of the CNS of the embryo shown in F. (H) Expression of myosin in the somites. Embryos of the marsupial frog G. riobambae are shown in I–L. (I) Expression of Lim1 in the notochord of a postgastrula. (J) Expression of Lim1 in the prospective pronephros of an early neurula. (K) Expression of Lim1 in the pronephros. (L) Expression of cardiac actin mRNA in the somites. b, blastopore; cns, central nervous system; n, notochord; p, pronephros; s, somite. [Scale bars: 50 μm (D); 100 μm (A and B); 200 μm (F and G); 250 μm (C, E, H, K, and L; and 500 μm (I and J).]