544 Mr. Hassall 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. Red Cray. Mam. Crag. Recent. 



6. Trivia retusa (Cyprsea retusa, Min. Con. t. 378. f. 2). 



Sutton. I Sutton. | j 



7. — globulosa, n. s. 



I Sutton. I I 



1. Erato Isevis, Gray (Erato cypreeola, Risso, Hist. Nat. desprin.prod. 



del Eur. vol. iv. p. 240. pi. 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, Sotv. (Min. Con. t. 478. Calpurna Leathesii, 

 Flem. Br it. Jn. p. 331). 



Sutton. 1 Walton Naze. [ | 



Corrigenda. 



Vol. vi. page 245. Note § refers to Cultellus, and not to Solen siliqua. 

 Do. do. Sphenia cylindrica is the young of Panopcea. 



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. 



GlUMOSvE. 



CYPERACEiE. 



Char. — Outline of pollen grain ovate- lanceolate ; extine covering 

 only a portion of the intinc, being deficient on cither side, and at the 



