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Show 444 MR.W.T. BLANFORD O N N E W MOLLUSKS. [June 24, valves in Dichelaspis and Conchoderma. In all this we perceive manifestation of, at least, a unity of design, if it be not simply an evidence of that latitude for diversity, or the susceptibility of divergent modification, impressed upon original types by the Great Author of Nature. Yet, though we may trace back divergent subtypes to one primary source, it would be unphilosophical to expect the mutual transmutation of any two such resultants into each other as contingent upon what the Darwinian theory is too often incorrectly assumed to involve. For, even if a tendency to revert to the original type, such as we see in unstable variety, were to manifest itself in any case, the effect of such a tendency would be the production of something very different from the collateral forms, instead of running into them, which a superficial thinker might suppose to be most natural; for tbe collateral forms themselves must have originated in special and protracted change developing great, though gradual, modification. EXPLANATION OF PLATES XXXIII. k XXXIV. PLATE XXXIII. Fig. 1. Parodolepas, attached in a group to one of the gills of Neptunus pelagicus. Natural size. 2. a. Group of three of the same little Cirripeds attached to one of the gill-flappers. Considerably enlarged. b. Lateral view of the single ovigerous lamella. c. Front view of the same, showing the emargination of its anterior border; also considerably enlarged. 3. Magnified view of Parodolepas neptuni, showing the course of the lines of growth, the shelly thickenings, and the minutely dotted surface of the valves. a. Pedicle. b. Scutum. c. Tergum. d. Carina. PLATE XXXIV. Highly magnified view of the oral apparatus of Parodolepas neptuni. a. Shelly support of the scutum (occludent segment). b. Occludent margin of the capitulum, showing lines or increments of growth decreasing both in thickness and length from before backwards. c. Labrum with minute dental points on its angular edge. d. Palp. «. Mandibles. /. Maxilla. g. External maxillae. h. Anterior pair of cirri. 6. Descriptions of new Land and Freshwater Molluscan Species collected by Dr. John Anderson in Upper Burma and Yunan. By W . T. B L A N F O R D , F.O.S., C.M.Z.S., &c. The following are the principal novelties in the large and very interesting collection made by Dr. John Anderson when accompany- |
