Miscellaneous, 77 



traction. This is particularly worthy of note now, since, recently, 

 Martin Barry (Miiller's Arch. 1850, p. 529) has advanced the doc- 

 trine of the spiral structure of muscular fibrillae. We have not 

 critically examined the ground on which Barry has based his views, 

 but from our knowledge of this tissue, the phases of its formation 

 from the earliest to the perfect state, and the various appearances it 

 presents in different parts of the animal kingdom, we are led to 

 venture the conjecture that its alleged spiral structure may be due to 

 irregularities and anomalies of contraction. — Silliman's Journal, 

 Sept. 1853. 



DESMARESTIA PINNATINERVIA, MONT. 



Some specimens of Alga, apparently new to our Flora, found float- 

 ing in Lough Foyle in August 1853, were transmitted by Mr. W. 

 Sawers of Londonderry to the late Meeting of the British Association, 

 which were pronounced by the authorities there present to be a state 

 of some common Laminar ia. There were, however, peculiarities in 

 the nervation and structure of the specimens which made this very 

 improbable, and in the absence of Dr. Harvey, some of the speci- 

 mens fell into my hands. After a minute examination and consi- 

 deration of the probable affinities of the production, I applied to 

 Dr. Montague for his opinion, and he at once referred it to his Des- 

 marestia pinnatinervia, figured from a specimen gathered on the 

 coast of Spain, in the October number of the ' Annales des Sciences 

 Naturelles' for 1842. The Irish specimens are indeed rather nar- 

 rower, but differ in no essential character. 



The species of Dr. Montagne is considered by J. Agardh as most 

 probably a state of the broad form of Desmarestia ligtdata, and this 

 view is confirmed by Messrs. Crouan, who refer it as a variety to 

 D. Dresnaji, Lamouroux, which is regarded as a form of D. ligulata 

 by J. Agardh. 



There is however a peculiarity of structure, as noticed both b}' 

 myself and Mr. Sawers, which no one seems to have recorded, namely 

 that the dark specks with which the specimens are sprinkled, and 

 which exist equally in Dr. Montague's plant, consist of red creeping 

 anastomosing beaded cells, just hke those of a young Callithamnion. 

 It is possible, however, that these may be extraneous. It would be 

 very desirable to compare very young specimens of the narrow form 

 of D. ligulata with Mr. Sawers' s plant, and till this is done, some 

 doubt must still exist as to the real nature of the production. The 

 yoimgest individuals that I have seen, sent to me by Mrs. Griffith, 

 though retaining their disc, are already repeatedly divided. — M. J. B. 



On Oligoneuria rhenana. By Dr. L. Imhoff. 



Every year, usually in August, many thousands of an Ephemera make 

 their appearance for several days together in this town (Basle). 

 During a considerable series of years they appeared at the end of 

 this month ; in the year 1834 they were observed at its commence- 

 ment; m 1851 they delayed their appearance until early in Septem- 

 ber. They are produced in the Rhine. A few hours before sunset, 

 but not earlier, a few of these insects may be seen fluttering along 



