182 Mr. W. Wilson on the Structure and Functions 



Dimensions {continued). inches, linos. 



Length from upper teeth to beginning of second dorsal 1 8 



first ditto 1 4 



anal 1 3 



ventrals 1 llf 



> pectorals 8 



edge of gill-cover 7f 



Diameter of the eye 2 



Length of snout before the eye 2 



Height of body 9 



Length of naked part of tail 4£ 



[To be continued.] 



XXIX. — On the Structure and Functions of the Pollen Gra- 

 nules. By William Wilson, Esq. 



In the e London Journal of Botany 5 for November 1842, the 

 results of a sedulous inquiry into the true structure and func- 

 tions of the pollen-collectors of Campanula were presented to 

 its readers ; and in the following month a letter from Arthur 

 Hill Hassall, Esq. appeared in the same Journal, directing 

 my attention to his own remarks on the same topic, published 

 in the ' Annals and Magazine of Natural History' for October 

 last. 



In acknowledging Mr. HassalPs courtesy, I beg to say that 

 I had not seen his paper, or it would have been discussed 

 when mine was written. 



Mr. Hassall has misunderstood me. I endeavoured to state 

 that the pollen granules are taken bodily into the interior 

 of the collecting hairs, and are ultimately lodged in the im- 

 bedded cavities ; but Mr. Hassall supposes that I allude only 

 to the pollen tubes. Having met with only one instance of 

 tubes from a pollen granule thus imbedded, I did not insist 

 upon it as a fact, but reserved that point for future inquiry. 



I must entirely dissent from Mr. HassalPs views. In the 

 first place, I cannot admit the propriety of terming that part 

 where the collecting hairs are found, a " stigma." He says 

 that the papillae of the stigmatic branches " resemble the hairs 

 in everything save length ;" but if the views of physiologists 

 are right, as I believe them to be, there must be an essential 

 difference between these papilla (rounded sides of vesicles of 

 cellular stigmatic tissue, according to Lindley,) and the col- 

 lecting hairs, concerning the anatomy of which Mr. Hassall 

 considers Brongniart to have given a satisfactory account ; for 

 the hairs are regarded by the latter as an extension of the cu- 

 ticle covering the whole surface of the style. 



In the second place, I deem it premature and hazardous, 



