. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CONUS ARTERIOSUS IN TARPON ATLANTICUS. 149 the proximall and distall rows appear to be approximately equal in size, this however is far from being the case, those of the distal row having a capacity far exceeding that of the proximal. The proximal valves are extremely fleshy at their attached margins, and shade rapidly into a thin semilunar area near'the free edge ; the edge itself is marked by a cord-like thickening, and is quite unattached, except at either end, where, having blended with the corresponding extremity of the
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CONUS ARTERIOSUS IN TARPON ATLANTICUS. 149 the proximall and distall rows appear to be approximately equal in size, this however is far from being the case, those of the distal row having a capacity far exceeding that of the proximal. The proximal valves are extremely fleshy at their attached margins, and shade rapidly into a thin semilunar area near'the free edge ; the edge itself is marked by a cord-like thickening, and is quite unattached, except at either end, where, having blended with the corresponding extremity of the other cusp, it is attached dorsally and ventrally to the mid-line of the bulbus a short distance beyond the conus. The distal valves are not so fleshy as the proximal, and the marginal semilunar area is very thin and profusely perforated. The margins are free except at their extremities, the dorsal ends of the right and left valves blend at the mid-longitudinal region of the bulbus, and be- come continuous with an elas- tic cord, the other end of which is attached to the dor- sal bulbus wall at its distal extremity. The ventral ex- tremities of the distal valves blend at their point of attach- ment in the mid-line at the junction of the proximal and middle thirds of the ventral bulbus wall. That the capacity of the dis- tal valves is much greater than that of the proximal, is shown by the fact that a probe can be passed 11 mm. into the former, and only 3 mm. into the latter. To illustrate this point, a frontal section passing ap- proximately through the mid-lateral line of another heart is shown in Fig. 3. 1 The terms proximal and distal are used with regard to the FIG. 3. Ventral face of a frontal sec- tion of the heart from the smaller, Tarpon its approximate source is indicated by the broken line in Fig. 3 ( X | )• •&> lumen of bulbus arteriosus; C, conus arteriosus ; D, cavity of right distal conus valve; P, cavity of left proximal conus valve ; Vt w
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
