FIGURE 4 in Melvicalathis, a new brachiopod genus (Terebratulida: Chlidonophoridae) from deep sea volcanic substrates, and the biogeographic significance of the mid­ocean ridge system *

FIGURE 4. Melvicalathis macroctena (Zezina, 1981) from the Galapagos Spreading Centre. A. Interior of dorsal valve of ZMB Bra 2014 showing descending branches of crura with incomplete transverse band, and internal ridges corresponding to external costal troughs. B. Close­up of previous photograph to show details of descending branches and incomplete loop. C. Spicular skeleton after dissolution of soft tissue. D. Close­up of triangular costae showing numerous closely spaced growth lines. E. Close­up of a valve of Eucalathis to show typical beaded tuberculate costae for comparison with D.