594 A Century's Progress in American Zoölogy. (October, 
A. R. Grote, W. H. Edwards, Henry Edwards, Sumichrast, H. 
C. Wood, A. Fitch, C. V. Riley, E. Norton, J. H. Emerton, C. 
Thomas, B. P. Mann, and others, are in most cases quite volu- 
minous, though mostly descriptive, while the fossil forms have 
been described by Dana, Scudder, Meek and Worthen, §. I. 
Smith, and O. Harger. Their anatomy has been studied by Leidy, 
Scudder, and Packard. 
The great work of Dana on the Crustacea of the United States 
Exploring Expedition placed him next to Milne-Edwards at the 
head of living authors in this department, and his essay on their 
geographical distribution is the starting-point for all such in- 
quiries. In this connection should be noticed the essays of Dana 
on cephalization in animals, suggested in the first place by his 
studies on the Crustacea. The North American species have been 
described by Say, W. Stimpson, J. W. Randall, L. R. Gibbes, 
S. I. Smith, Hagen, Packard, and O. Harger, and the fossil 
forms by Green, Hall, Billings, Stimpson, and others. 
The intestinal and higher worms have been worked up by D. 
Weinland, Girard, Leidy, Wyman, Stimpson, and Verrill; and 
of the aberrant classes, the Polyzoa have been carefully studied 
anatomically by A. Hyatt, the Brachiopoda by E. S. Morse and 
W. H: Dall, and several species of Tunicata described by C. A. 
Lesueur, Tellkampf, Louis and A. Agassiz, Verrill, and Packard ; 
while their development has been studied by Morse. 
The Molluses of North America have been elaborated by Say, 
Gould, Lesueur, Rafinesque, Haldeman, I. Lea, T. A. Conrad, 
C. B. Adams, Stimpson, the two Binneys, J. W., Mighels, J. 
P. Couthouy, E. Ingersoll, A. Agassiz, T. Bland, T. Prime, 
O. A. White, F. S. Holmes, O. St. John, C. F: Hartt, R. Batt: 
bun, O. A. Derby, Whitfield, N. S. Shaler, Whiteaves (of Canada) : 
and other palzontologists, and the quaternary species studied by 
Holmes, Dawson, Stimpson, Packard, Verrill, Matthews A 
others. Their anatomy has been studied by Leidy; Wym™ 
Morse, Dall, and W. K. Brooks. 
The Radiates (including the Ccelenterates and Echinoderms) 
have been carefully elaborated by Louis and A. Agassi 3 
by Say, Stimpson, E. Desor, Ayres, Macrady, H. ¢: a 
T. Lyman, and Verrill; while Dana’s elaborate report oP io 
Zoöphytes of the United States Exploring Expedition took 
epee Rea ose ead ian FF 
Sse eae eke yee 
