TRANSACTIONS OF THE SECTIONS. 73 



and partly of masters accustomed to the methods of piihlic schools. He stated that 

 at almost every school something was being done, but that the plans mainly 

 adopted were three; viz., 1. Modem schools in which science was made a part of 

 the course ; 2. occasional and compulsory lectures, of which notes were taken by 

 the boys ; and 3. a voluntary system, by which boys were encoio-aged rather than 

 compclicd to make themselves acquainted with various sciences. Euo-bv is the only 

 school at which science is now regularly and completely introduced ; and the author 

 therefore described the system there introduced, and the no less characteristic 

 voluntary sj^stem which has been established with much care at Harrow, and which 

 is working most advantageously. Finally, the author suggested his o-\vn scheme 

 which was a combination of the voluntary and compulsory sj-stenis for which in 

 the case of many boys ample time could be gained by a wise abandonment of the 

 practice of Greek and Latin composition — an abandonment which (in the case of 

 all but first-rate scholars) he warmly advocated ns most desirable after a certain 

 age. 



On the Power which some Rotifers have of attacJiinr/ themselves ly means of a 

 Thread. By E. Garnee, F.L.S. 

 In this short paper the author observed that Eotifers are not common in sea- 

 water, though one, Colurm uncinatus, may he foimd in any tanli. That especially 

 noticed, hovfQxev, Synchata Baltica, is more choice in its habitat, though it may 

 always be found in water from the mouth of the Mersey, from Ilhj-1, or Llan- 

 dudno. The author has not noticed it to be luminous. It evidently has the power of 

 forming a very fine thread from its posterior extremity, by which it attaches itself 

 to other bodies ; and when so attached it performs those remarkable circular move- 

 ments described by Gosse ; its ciliated side processes being powerful locomotive 

 organs. During the performance of these movements the thread may be inferred 

 to be present, from small particles adhering, and it may be made visible with the 

 highest power of the usual microscope, } inch : the Rotifer can snip it with its 

 pincers at its pleasure, when it goes off with great velocity. Other Rotifers may 

 have a similar power, as indeed is mentioned by Cohn in the common Hydatina. 



Variations in the Great Arterial Blood-vessels. 

 By George Duncan Gibb, M.A., M.D., LL.D., F.G.8. 



Deviations in the origin of the great vessels from the aorta were seldom or 

 never recognized during life ; whether they exerted any liability or disposition to 

 morbid action, the author thought improbable. In the first of his examples the 

 aorta ga^e olf four branches, instead of the usual three. These were the left 

 carotid and subclavian, arising in the usual manner, and the right carotid and 

 subclavian, each arising direct from the arch of the aorta by a distinct and separate 

 trunk, there being an absence of the innominata. The two vessels on the right 

 side were larger than the left ; the left carotid was the smallest of the four. The 

 com-se of these vessels was the usual one, but the laryngeal branch of the superior 

 thyroid artery of the left side perforated the thyroid cartUage, instead of passino- 

 inwards through the thyro-hyoid membrane in the usual manner. Both femoral 

 arteries, and the left great ischiatic ner^-e varied in their division ; all the arteries 

 of the extremities were calcified into hard unyielding cylinders. 



In the author's second instance, the main trunk or ascending portion of the arch of 

 the aorta divided into two great branches, the first of which subdivided into the 

 innominata and left carotid, the latter crossing the trachea obliquely upwards to 

 the left side ; the innominata divided into the two usual branches of right sub- 

 clavian and carotid. The other subdivision of the arch was into the left subclavian 

 and descending aorta, both vessels taking their usual course. If his interpretation 

 of this peculiarity were correct, the author considered it a unique instance of divi- 

 sion of the aorta into two branches which in their subdivision gave oft" the proper 

 trunks. No similar example had been found, even in Mr. Quain's oreat work- 

 and the inference was that it was unique. The division of the aorta in this second 

 example was not unlike that of the abdominal aorta into the two iliacs. 



