8 SAN DIEGO SOCIETY OF NATURAL HISTORY 
BARTON (Donald C.)—Continued 
Cheirurus Beyrich genotype Ch. insignis Beyr., with figure. 
The genus can be readily distinguished from Ceraurus and Ceraurinus by the tri- 
angular basal lobes of the glabella, the inner points of which are not separated by a 
portion of the glabella; also by the hypostoma. 
Crotalocephalus Salter, genotype C. Sternbergi Boeck. Fig. of head in text. 
Ceraurinus Barton, genotype C. marginatus, Fig. in text. 
Distinguished from Cheirurus and Ceraurus by the rather large ovate to sub- 
rectangular basal glabellar lobes. 
Ceraurus Green, genotype C. pleurexanthenus. Fig. in text. 
ew 
The author does not include Youngia, 4 genus described by Lindstrom, with Cheiru- — 
rus trispinous for its type, in 1885—not Youngia, Jones & Kirby, 1886. 
The genus has long genal spines with aculate occipital ring, and may be compared 
with Nieskkowskia. 
Lindstrom genus has a peculiar axis to the thorax, the first axial joint being fur- 
nished with a pair of small lateral processes on the anterior margin. 
Barbour (KE. IH.) Carboriferous Eurypterids of Nebraska. 
Am, Jour. Sci., 4th ser., vol. 38, 1914, p. 507, figs. 1 and 2. 
The author describes Eurypterus (Anthraconectes) nebraskensis nov., from the Coal 
Measures near Peru, Nebraska. 
The main features are the vermiform appearance, the long spatulate paddles, and 
the spinous ridges upon the last 5 tergites of the post abdomen. 
Fig. 2 represents an unnamed sp. 
Basser (Ray 8.) Bibliographie index of American Ordovician and 
Silurian Fossils. 
U. S. Natl. Mus. Smithsonian Inst. Bull. 92, volumes 1 and 2, 1915. 
The author gives a historical index to the genera and the North American species 
of Paleozoic crustacea during Ordovician and Silurian epochs. 
Beecher (Charles E.) Notes on Cambrian fossils of St. Francis County, 
Missouri. 
Am. Jour. Sci., ser. 4, vol. 12, 1891, pp. 362-363. 
On the thoracic legs of Triarthrus. 
Am. Jour. Sci., ser. 3, vol. 46, 1893, pp. 469-470. 
The larval stages of Trilobites. 
Am. Geol., vol. 16, 1895, pp. 166-197, plates 8-10. 
The author gives a review of larval stages of Trilobites. 
Analysis of variations in Trilobite larvae. 
Antiquity of the Trilobite. 
Restoration of the protaspis, etc. 
The author remarks in regard to the larval stages cf the following Trilobites from 
the Cambrian: 
Solenopleura robbi Hartt., after Matthew. 
Larva very minute and circular in outline; the glabella is obscurely annulated and 
extends to the anterior margin, where it is expanded. 
The neck ring is only one, well defined; abdominal portion is less than one-third 
the whole length, and is limited by a slight transverse furrow; no traces of eyes or 
free cheeks. 
Liostracus onangondianus Hartt., after Matthew. 
