190 



SCIENCE. 



[N. S. Vol. IV. No. 85, 



trally and approximating them dorso-an- 

 teriorly. Compensation takes place, how- 

 ever, by the development of a third adduc- 

 tor muscle, which occurs at the lower angle 

 of the pallial sinus. This adductor mus- 

 cle is in fact composed of pallial muscles di- 

 verted to this use. Such a muscle occurs 

 in Zirphsea and Teredo and another Pid- 

 dock which I have examined, said to have 

 been brought in ballast from Panama. 



By means of muscles arranged with re- 

 spect to the point of contact, as these are, the 

 valves of the shell can be moved mutually 

 in any plane excepting a dorso- ventral one. 

 The antero-ventral margin of the shell of 

 the working form is armed with teeth, which 

 are constantly renewed by shell accretion, 

 forming a good rasp. Certain scratches in 

 the wall of the burrow show that this rasp 

 has been used in enlarging the hole, the an- 

 terior mantle pad and foot being used as 

 fulcra. There are, however, other scratches 

 at the apex of the burrow which indicate 

 that the foot armed with sand serves also 

 as a drill, but all attempts to watch the op- 

 eration have so far been futile. 



Specimens of this form have been found 

 by the writer showing all degrees of de- 

 generacy. Francis E. Lloyd. 



Pacific Univeesity, 



FOEEST Geove, Oeegon. 



SIB JOSEPH PBESTWICH. 

 The Nestor of English geologists — Sir 

 Joseph Prestwich — late professor of geology 

 at Oxford, died on the 23d of June, last, at 

 the ripe age of 84 years. The life of Prof. 

 Prestwich covers the most eventful period 

 in the past of geology. The problem whose 

 solution has established the principles of 

 the new science all arose during his life- 

 time, and of these all he could say with 



truth 



' ' quaeque ipse vidi 

 Et quorum pars magna f ui. ' ' 



Born near London on March 12, 1812, 



he received his early education partly in 

 England and partly in France, becoming^ 

 later a student of University College, where 

 his attention was chiefly turned to chemistry 

 and natural philosophy, geological study 

 not being then a recognized part of any 

 course. While there he founded among hi& 

 fellow students the Zetetical Society, com- 

 posed of about 14 young men who arranged 

 to lecture to one another for the purpose of 

 mutual improvement. 



Necessity, rather than inclination, turned 

 his course into business, in which he was 

 closely occupied for nearly 40 years, but 

 during this long time his thought and his 

 holidays were employed in his favorite 

 topic, geology. It was his enthusiasm and 

 stern earnestness that enabled him to ac- 

 complish so much in hours that most men 

 would have devoted to mere amusement. 

 The necessary books and travel were ob- 

 tained by the strictest self-denial in per- 

 sonal expense, sometimes, perhaps, to an 

 excessive degree, but the results became 

 manifest in a series of investigations that 

 rapidly brought him to the front, and re- 

 sulted in his appointment to the chair at 

 Oxford in 1874. 



To enumerate the successive publications 

 that came from his pen would scarcely befit 

 this notice. A glance at the many prob- 

 lems that engaged his attention and which 

 were in part or altogether solved by his 

 efforts will prove more instructive and in- 

 teresting. One of his earliest papers ap- 

 peared in the transactions of the Geological 

 Society of London in 1836, and contains 

 an investigation of the Coalbrookdale coal 

 field, but his attention was soon directed to 

 the English and French Tertiary strata and 

 their correlation, and from these he passed 

 to the younger or quaternary deposit on 

 which most of his later work was done. 



In several years reports had been current 

 of the occurrence of human relics in the 

 form of flint implements in gravels of very 



