544 Mr. H assail on the Structure of the Pollen Granule. ' This also varies considerably in size, from eleven-sixteenths to less than one-fourth of an inch. Cor. Crag. Bed Crag. Mam. Crag. Recent. 6. Trivia retusa (Cyprsea retusa, Min. Con. t. 378. f. 2). Sutton. I Sutton. | | 7. — globulosa, n. s. I Sutton. I I 1. Erato Isevis, Gray (Erato cyprseola, Risso, Hist. Nat. desprin.prod. del' Eur. vol. iv. p. 240. \i\. 7. f. 85. Margin ellavoluta, Flem. Brit. An. p. 335. Cyprsea voluta, Mont. Test. Brit. t. 6. f. 7. Voluta laevis, Don. Brit. Shells, t. 145). 2. — Maugerise, Gray (Sow. Conch. Illust. f. 47). Sutton. I Sutton. | | West Indies. The West Indian specimens are generally a little smaller and rather more delicately formed than the crag shell. 1. Ovulum Leathesii, Sow. (Min. Con. t. 478. Calpurna Leathesii, Flem. Brit. Jn. p. 331). Sutton, j Walton Naze. | | Corrigenda. Vol. vi. page 245. Note § refers to Cultellus, and not to Solen siliqua. Do. do. Sphenia cylindrica is the young of Panopaa. Do. page 251. Cardium nodulosum is Cardium nodosum, Turt. Do. do. Nucula tenera is Area tenuis of Mont. LVII. — Observations on the Structure of the Pollen Granule, considered principally with reference to its eligibility as a means of Classification. By Arthur Hill Hassall, Esq., M.R.C.S.L., Corresponding Member of the Natural History Society of Dublin. [Continued from vol. viii. p. 108.] [With 6 Plates.] The second portion of this communication comprises a par-ticular description of the principal forms of pollen granules met with by the author during his investigations^ together with the names of all the plants examined, arranged accord-ing to Lindley's ^ Natural System/ which is followed in every particular, save that the order of arrangement is reversed, the lower tribes of Phanerogamic plants being first enumerated. VASCULARES. ENDOGENS OR MONOCOTYLEDONS. Glumos^. Cyperaceje. CiiAR. — Outline of pollen grain ovate -lanceolate ; extine covering only a portion of the intine, being deficient on either side, and at the
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