140 SAN DIEGO SOCIETY OF NATURAL HISTORY 
The position of the Merostomata. 
Geol. Mag., Decade v, No. 7, July, 1913, p. 293, two text figures. 
The author gives a sketch of the genus from McCoy’s weird restoration of Ptery- 
gotus problematicus, in fifth edition of Lyell’s Manual of Elementary Geology, 1855, 
p- 420. 
Pterygotus Anglicus. Dithyrocaris Scouleri 
Also the further discoveries of Pterygotus, made by Robert Slimon in the Geol. 
Sur. Memoir in 1859, illustrated by 16 plates and text figures. 
Salter contributed a restoration of Pterygotus anglicus to Murchison’s Siluria, 1859, 
edition. He gives only two pairs of appendages to the head. The operculum is 
placed in front of the mouth, and the lower lip or metastoma is absent. 
Dr. Nieszkowski, in his paper on Eurypterus remipes, gives restorations of the up- 
per and under sides of Eurypterus, showing the appendages of the mouth in situ and 
the thoracic plates on the under side of the body. 
Other restoration of several forms of Pterygotus Stylonurus Eurypterus, without de- 
scriptions, are given in David Page’s Advanced Text Book of Geology, 1859, all more 
or less correct. 
Excellent descriptions and figures of American species of Eurypterus and Pterygotus 
are given by James Hall in Paleont. New York, vol. 3, pt. 1, pp. 382-419, 80 plates 
and 10 additional plates, the accuracy of which still remains unchallenged. 
Mr. J. W. Salter, in the Quart. Jour. Geol. Soc., 1862 and 1863, contributed descrip- 
tions of Eurypterus and allied form of Pterygotus. 
Dr. Henry Woodward figured and described a very complete example of Slimonia 
acuminata in the Intellectual Observer, 1863, vol. 4, p. 229; also of Eurypterus lanceo- 
latus in the Geol. Mag., 1864, vol. 1, p. 107, pl. 5, figs. 7-9. In 1865 he figured and 
described Stylonurus scoticus, S. Powertei, 8. Symondsi Hemiaspis limuloides in the 
