sel 
~ 
Te) 
BIBLIOGRAPHY OF PALAOZOIC CRUSTACEA 
RAYMOND (Percy E)—Continued 
form elongate, oval; cephalon and pygidium, nearly equal, both rounded, smooth and 
convex; glabella quadrate, outlined by deep, narrow dorsal furrows and extending to 
the 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. Type Bathyurus 
quadratus Billings. 
Notes on the ontogeny of Isotelus gigas DeKay. 
Bull. Mus. Comp. Zoology Harvard College, vol. 58, No. 5, 1914, p. 247-263, with 
3 plates. 
The author gives the ontogeny of three Asaphids, namely, Isotelus gigas, I. maxi- 
mus and Basilicus barrandei. Raymond remarks on: 
I. Basilicus stage. The glabella is convex, narrowed behind, with a median tu- 
berele 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 the 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 both become smooth and the axial lobe 
widens, as in the adult of Isotelus. 
IV. IJsotelus gigas stage. The head and tail becomes triangular and the spines 
are lost from the genal angles, a combination of characters distinguishing this species. 
The author remarks in regard to /sotelus Iowensis Owen, that it is so closely allied 
to J. 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 Isofelus iowensis, has long 
genal spines extending to the Sth, 6th and 7th segments of the thorax, 
Isotelus maximus Locke. 
The author remarks that the common asaphids at Cincinnati are Jsotelus gigas, I. 
maximus, I. latus, an undescribed species and one of the genus Onchometopus. 
The four more common species of Isotelus in the Middle and Upper Ordovician are 
classed as follows: 
A. Shield about three-fourths as long as wide. 
a. Adult without genal spines, shield subtriangular, /. gigas. 
° b. Adult with genal spines, shield rounded, J. ioavensis. 
B. Shields less than three-fourths as long as wide, regularly rounded. 
a. Adult without genal spines, I. latus. 
b. Adult with genal spines, I. maximus. 
The author places Proetus spurlocki Meek as a young Isotelus, probably that of 
I, maximus. 
The article closes with a description of Basilicus Barrandei Hall, the author refer- 
ring Asaphus romingeri Wale. and A. wisconsensis Wale. to the species, including 
Ptychopyge ulrichi Clarke, under the same. 
Notes on the ontogeny of Paradoxides, with deseription of a 
new species. 
Bull. Mus. Comp. Zoology Harvard College, vol. 58, No. 4, 1914, pp. 225-244, plates. 
The author describes and illustrates Paradoxides Harlani Green, and a new species, 
under the name of Paradoxides Hayawardi, with a Bibliography of the genus. 
The author classes the genus after Ford into two groups: 
A. With the second segment of the thorax prolonged beyond the others. To this 
group belong the Bohemian and South European species. 
