BIBLIOGRVPHY OF PAIj.EOZOIC CRUPTACEA 79 



RAYMOND (Percy E)— Continued 



form elongate, oval; cephalon and pygidium, nearly equal, both roinuied, smooth and 

 con\ex ; glabella quadrate, outlined by deep, narrow dorsal furrows ami extending to 

 tiie very narrow elevated anterior rim; fixed cheeks wide, eyes small and far from 

 the glabella; thorax of 9 segments; pygidium almost semi-circular, unsegmented ; axial 

 lobe elevated, extending nearly the whole length. No concave border. Tvpe Bathyunis 

 quadratus Billings. 



Notes on the ontoyonv of Isohlnx f/if/as DcKny. 



Bull. Mus. Comp. Zoology Harvard College, vol. 5S, No. 5, 1914, p. 247-263, with 

 3 plates. 



The author gives the ontogeny of three Asaphids, namely, Lsotrliis ,t,''A''". I- m<i.\i- 

 iniis and Basilicus harraruiei. Raymond remarks on: 



I. Basilicus stage. The glabella is convex, narrowed behind, with a median tu- 

 bercle and basal lobes. The brim is wide and horizontal; the cephalon semi-circular 

 in outline; the genal angles produced into long spines; the axial lobe of the thorax 

 is narrow; the pygidium has a prominent axial lobe, and tlie pleural lobes of the 

 pygidium are ribbed. 



II. Ogygites stage. The glabella soon becomes flattened and the facial sutures in- 

 termarginal, as in the adult of Ogygites. 



III. Isotelus stage. The head and tail hoth become smooth and the axial lobe 

 widens, as in the adult of Isotelus. 



I v. Isotdus f^ns^cis stage. The heati and tail iiecomes triangular and the spines 

 are lost from the genal angles, a combination of characters distinguishing this species. 



The author remarks in regard to Isotelus loivensis Owen, that it is so closely allied 

 to /. gigas, that where the two species occur together, as at Trenton Falls, it seems al- 

 most like hair-splitting to recognize two species. The adult Isotelus ioiverisis, has long 

 genal spines extending to the 5th, 6th and 7th segments of the thorax. 



Isotelus maximus Locke. 



The author remarks that the common asnphids at Cincinnati are Isotelus gigas, I. 

 maximus, I. latus, an undescribed species and one of the genus Onchometopus. 



The four more common species of Isotehis in the Middle and Upper Ordovician are 

 classed as follo\vs: 



A. Shield about three-fourths as long as \vide. 



a. Adult without genal spines, shield subtriangular, /. gigas. 



b. Adult with genal spines, shield rouiuled, /. ioiL-ensis. 



B. Shields less than three-fourths as long as wide, regularly rountled. 



a. Adult without genal spines, /. latus. 



b. Adult with genal spines, /. maximus. 



The author places Proetus spurlocki Meek as a young Isotelus, probably that of 

 /. maximus. 



The article closes with a description of liasilieus Barrandci Hall, the author refer- 

 ring .'Isap/ius romingeri Wale, and ,7. icisconsejtsis Wale, to the species, including 

 l^lyr/iopyge ulriclii Clarke, untlcr the same. 



— Notes on the ontoticiiy of Parndoxidcs. witli (Icsci'iption of a 



now sppcios. 



Bull. Mus. Comp. Zoology Harvard College, vol. 5S, No. 4, 1914, pp. 225-244, plates. 



The author describes and illustrates ParaJoxides Harlaui (Ireen, and a new species, 

 under the name of Paradoxides Ilayivardi, witli a Bibliography of the genus. 



The author classes the genus after Ford into two groups: 



A. W'ith the second segment of the thorax prolonged beyond the others. To this 

 group belong the Bohemian and Snutli European species. 



