368 Mr. W. Thompson on the Occurrence of a Surf Scoter. 



of multiplication by division, are not sufficient to explain all cases 

 of cell- development, — I allude particularly to the production of 

 free cells in the cavity of a parent-cell, such as occurs in the for- 

 mation of spores and pollen. Supposing that this is not effected 

 in the way described by Schleiden, namely by development from 

 nuclei, it is necessary to suppose either with Nageli that the pri- 

 mordial utricle divides into distinct portions and becomes de- 

 tached from the cell-wall before it begins to secrete membrane, 

 or that the new cells formed within the parent-cell in a manner 

 represented in the figures, subsequently become free by the solu- 

 tion of those layers of membrane deposited immediately upon the 

 primary wall. 



This is a subject of considerable difficulty, especially as an in- 

 ternal formation, such as is implied in all these theories, throws 

 no light upon the external markings which are produced in de- 

 finite arrangements or pollen grains, spores, &c. These points 

 remain for future investigation. 



EXPLANATION OF PLATE VIII. 



Fig. 1 . Very young capitate hairs from the scales of the buds of Achimenes 



grandijlora ; treated with iodine. 

 Fig. 2. Somewhat older specimens. 

 Figs. 3, 4. Older specimens exhibiting the continuation of the primordial 



utricle through the whole length ; kept in spirit some days. 

 Figs. 5, 6, 7, 8. Specimens where some of the septa are incomplete, others 



perfect; treated with iodine. 

 Fig. 9. The lower part of fig. 8. more highly magnified, exhibiting the new 



internal membrane. 



XL. — Notice of a Surf Scoter, Oidemia perspicillata, Linn, (sp.), 

 obtained on the coast of Ireland. By William Thompson, 

 Pres. Nat. Hist, and Philos. Society of Belfast. 



A beautiful adult male bird of this species was shot at Bally- 

 holme, Belfast Bay, on the 9th of September 1846, by Snowden 

 Corken, Esq. It was alone, about two hundred yards from the 

 shore, allowed three shots to be fired at it before attempting to 

 dive, and was killed at the fourth or fifth shot, on reaching the 

 surface after having dived*. Two birds of this species had a day 

 or two before been observed in company in the same locality, and 

 one was seen several times in the course of a few weeks after the 

 subject of this notice had been killed. " The weight of the spe- 

 cimen was 1 lb. 14 oz. ; its length 21 inches; wing from carpus 



* Audubon remarks, that " it is an uncommonly shy bird, and therefore 

 difficult to be obtained, unless shot at while on wing, or when asleep, and 

 as it were at anchor on our bays, or near the shore, for it dives as suddenly 

 as the Velvet and Scoter Ducks, eluding even the best percussion-locked 

 guns." — Orn. Biog. vol. iv. p. 163. 



