. Allan Hancock Pacific expeditions. [Reports]. Scientific expeditions. 9. Anomalous male first pleopods of Galapagos Mithrax species. A. Mithrax (Mithrax) belli, mm male {Velero III Sta. 163-34), x B. Same, terminal portion, x C. Mithrax (Mit/iraculus) nodosus, mm male {Velero III Sta. 42-33), x Remarks: The unusual male first pleopod (see text-figs. 9A, B) deserves special comment. The heavy basal portion appears to be cor- related with the very wide abdomen noted by Rathbun above. The tubular extension which serves as an intromittent organ, unlike anything so fa
. Allan Hancock Pacific expeditions. [Reports]. Scientific expeditions. 9. Anomalous male first pleopods of Galapagos Mithrax species. A. Mithrax (Mithrax) belli, mm male {Velero III Sta. 163-34), x B. Same, terminal portion, x C. Mithrax (Mit/iraculus) nodosus, mm male {Velero III Sta. 42-33), x Remarks: The unusual male first pleopod (see text-figs. 9A, B) deserves special comment. The heavy basal portion appears to be cor- related with the very wide abdomen noted by Rathbun above. The tubular extension which serves as an intromittent organ, unlike anything so far encountered in the family, would at first appear to indicate separate descent. However, the characters which relate the species to the genus Mithrax, the subgenus Mithrax, and the superspecies represented by M. (M.) verrucosus in the Atlantic and by M. (M.) belli in the Pacific are so many and detailed that there is no thought of erecting a separate group on the basis of this aberrant gonopod alone. Rather, it would appear to represent a mutation which has spread to an entire insular population and which would serve as an effective species isolating mechanism should opportunity for interbreeding with mainland species Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Allan Hancock Foundation. Los Angeles, University of Southern California Press
Size: 950px × 2631px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectio, booksubjectscientificexpeditions
