8 SAN DTEGO SOCIETY OF NATTTRAL HISTORY 



BART ON (Donald C.)— Continued 



Cheirurus Bc\ rich g,enotype C.li. iii.siyjiis Beyr., with figure. 



The genus can he 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. Sterubergi 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. pleurcxantlicnus. Fig. in text. 



The" author does not include \'oungia, a genus described by Lindstrom, witli Cheiru- 

 rus Uispinous for its type, in 1885 — not Voungia, 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 tlie thorax, the first axial joint being fur- 

 nislied with a pair of small lateral processes on the anterior margin. 



Barbour (E. 11.) Carboniferous Earyj)terids of Nel)raska. 



Am. Jour. Sci., 4th ser., vol. 38, 1914, p. 507, figs. 1 and 2. 



The author describes Eurypti'rus { .1 rithraconcdcs) uelnaskensis nov., from the Coal 

 Measures near Peru, Nebraska. 



The main features are the \ermiform appearance, the long spatulale paddles, and 

 the spinous ridges upon the last 5 tergites of the post abdomen. 



Fig. 2 represents an unnamed sp. 



Basser (Ray S.) l^il)lioiirapln(' index of Anicrican OrdoYieian and 

 .Silurian Fossils. 



U. S. Natl. Mus. Smithsonian Inst. Bull. 92, volumes 1 and 2, 1915. 



The author gives a iiistorical index to the genera and the Nortli American species 

 of Paiajozoic Crustacea during (Jrdovician aiui Silurian epochs. 



Beecher (Charles E.) Notes on Cauibrian fossils of St. Francis County, 

 j\lissouri- 



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 autlior gives a review of larval stages of Trilobites. 



Analysis of variations in Trilobite lar\'ae. 



Antiquity of the Trilobite. 



Restoration of the protaspis, etc. 



The author remarks in regard to the larval stages of the following Trilobites from 

 the Cambrian: 



Soletiopleura rohh'i 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 limiieti b\ a slight transverse furrow; no traces of eyes or 

 free cheeks. 



Liostraciis onangondianus Hartt., after Matthew. 



