BIBLIOGRAPHY OF PALAMOZOIC CRUSTACEA 81 
RAYMOND (Percy E)—Continued 
The author remarks on the order Hypoparia in Beecher’s classification. Since the 
young of practically all primitive Trilobites lack eyes on the dorsal side, Beecher 
grouped all Trilobites in which absence of eyes was a primary characteristic in his 
First Order, Hypoparia. Recent studies and discoveries have led a number of in- 
vestigators to the conclusion that blindness in the Agnostidae, Eodiscidae, Trinu- 
cleidae, Raphiophoridae and Harpedidae is secondary and a degenerative not primitive 
characteristic. If their position is well taken, then the order should disappear and the 
families be distributed in the two orders which remain. 
The author gives a figure of Agnostus nudus exhibiting the facial suture and free 
cheeks. The facial sutures are not marginal, but intra-marginal. They meet in an 
obtuse angle at the front and run backward just inside the margin, somewhat like the 
course of the pre-ocular portion of the suture in an Homalonotus. The sutures keep 
within the angles, so that the fixed cheeks bear the genal angles—a Proparian char- 
acteristic. The sutures in this manner cut otf a yoke-shaped area, bounded outside by 
the facial sutures and inside by a marginal edge, which follows the outline of the 
base of the elevated portion of the cranidium (the glabella). Both limbs of the yoke 
taper backward to a point, and it forms a continuous plate, with no vertical or 
epistomal sutures. This plate has the position and aspect of a large epistomal plate, 
but, whether called an epistoma or free cheek, the sutures which separate it from the 
cranidium must be interpreted as the facial sutures. 
The author includes only one family under Hypoparia, that of Eodiscidae, Eodiscus 
as defined by Matthew, 1896, Mollisonia Walc. and Pagetia Walc. The discovery of 
Pageria vootes and P. clytia, which bear eyes very close to the lateral margins, seems 
to be a confirmation of the previous supposition that the Eodoscidae have ventral free 
cheeks. 
Dr. Raymond does not note Microdiscus caudatus Delgado, a species with a mu- 
cronated pygidium and with free cheeks, from the Cambrian of Portugal. 
Delgado’s description, p. 349, pl. 3, fig. 12, Fauna Cambrian Haut Alemtejo. 
Remarks: “La suture faciale, mais il semble que 4 partir de l’angle anterieur de 
loeil; il décrit une courbe tres courbe, ayant la convexité tournée en dehors, allant 
traverser le contour exterieur de la téte prés de la projection de l’oeil; postérieurement 
il décrit aussi une courbe analogue, atteignant le contour intérieur en dedans de la 
projection postérieure du centre de figure de l'oeil.” 
I would suggest the new genus Delgadoia for this species as a type. 
Dr. Raymond remarks on Shumardidae, that these little trilobites are too much of a 
puzzle to be discussed at any length. 
The paper ends in a discussion of Harpedidae and Trinucleidae. 
The author would not include Orometopus in the last family, and remarks: “It is 
so unlike any of the Trinucleidae, that the burden of proof that it belongs to that 
family should be upon those who placed it there.” 
Under Raphiophoridae, a figure of Lonchodomas portlocki Barr., which shows on 
the ventral side of the head, a yoke-like plate similar to that of 4gnostus nudus, but 
instead of being confined to the ventral side it laps over the margins up onto the dorsal 
side, being separated from the cranidium by a suture which has the course of the or- 
dinary facial suture. The absence of eyes makes the analogy with the ventral plate 
of Agnostus the more complete. 
Having reviewed all the families of the Hypoparia the author remarks that there 
seems to be a tendency in two directions—in Agnostus and Eodiscidae towards the Pro- 
paria, and in the Trinucleidae and Raphiophoridae towards the Opisthoparia. 
Mesonacidae: 
The author remarks there can be no doubt that Elliptocephala asaphoides and other 
