BARKER — ON THE ROSEHILL PARROKEET. 153 



which genera, along with some others, as well as some as yet uncertain 

 forms, make up the old incongruous genus Palmoglcea (Kiitz.). 



That in Spirotsenia, as in other Desmidiacese, the new growth, dur- 

 ing self- division, is produced between the two older halves, seems evi- 

 denced by the blunt extremities as seen after division, and by the 

 varying position of the nucleus as regards the extremities. The genus 

 SpirotEenia, in fact, seems as truly to belong to Desmidiacese as do 

 Penium, Cylindrocystis, or Mesotsenium ; the place, in fact, which has 

 been assigned to this genus so long, even though it were but provi- 

 sionally, seems to be its legitimate position, sustained as that view is 

 by the fact, now here for the first time recorded in two species, that its 

 fructification takes place by conjugation. 



THURSDAY EVENING, JUNE 6, 1867. 

 Robert Callwell, M. R. I. A., President, in the Chair. 

 The Minutes of the preceding Meeting were read, and signed. 



Dr. John Barker sent for exhibition a Skeleton of Platycercus eximius, 

 or Rosehill Parrokeet. In Dr. Barker's absence, the Honorary Secre- 

 tary read the following letter upon the skeleton exhibited : — 



"The matters which I think worthy of attention connected with 

 the skeleton of the Parrokeet exhibited are — first, the absence almost 

 entirely of furcula, and the immense size of the breast-bone, its depth 

 being almost as great as in any other bird I have dissected. It may be 

 in the recollection of the Society that I exhibited a specimen of a Par- 

 rokeet in which the furcula was altogether absent. This was what 

 was called the Carolina parrot. In this bird there was not a vestige of 

 furcula, and although the keel of the breast-bone was very deep, it is 

 stated that its flight is neither long nor vigorous. In the present in- 

 stance there is, as can be well seen in the skeleton on the table, a rudi- 

 ment of a clavicle on each side close to the corocoid bone, and the depth 

 of the keel of the sternum is very remarkable. The structure, too, in 

 the keel shows an arrangement of the fibres and bone cells suitable for 

 giving this appendage a great increase of strength, in a longitudinal di- 

 rection, somewhat analogous to the form of Fairbairn's lifting crane ; 

 the sternal muscles were of very great size and weight, and, being placed 

 so far back abdominally, the direction of their action would be upwards 

 greatly and backwards, and would give the bird a power of upward 

 flight, which its long tail would well direct ; while by the muscles of 

 flight having their origin from the most moveable parts of the ribs and 

 sternum, its flight would be expected to present a series of curves, like 

 some of our smaller birds, to allow of the movements of respiration. Now, 



35_44, Peniurn; also " Quarterly Journal of Microscopical Science," vol. iv., N. S. 

 p. 109, PL VI. 



