No. 89.J 



117 



BARRANDIA VERMONTANA*. 

 The accompanying figure of B. vermontana illustrates also the character of the 

 cephalic shield, and the greater strength and extension of the third articulation of 

 the thorax. The fragment of thorax and p3'gidium, heretofore referred to this 

 species (Twelfth Annual Report of the Regents), prove, on farther examination, 

 to be parts of the following or a similar species there referred to Peltuka. 



Baruandia veumontana. 



The head and part of the thorax. The remaining parts of the 

 animal are unknown. 



In my examinations of these Trtlobites, I had hoped to unite the three forms 

 heretofore described, under a single genus; but on more careful comparisons, I find 

 that the one before referred to Peltura is so dissimilar, that I am unable, by any 

 proper extension of the generic characters of Babrandia, to include it in the same 

 genus. In the specimen figured, and in two others which appear to possess the 

 thorax and pj^gidium entire, there are but eleven thoracic segments; the third 

 segment is not enlarged and produced as in Barrandia, but, on the other hand, 

 the anterior segments, to the number of five or six, are little prolonged at their 

 extremities : the prolongation increases in the posterior segments, while the last 

 one of the thorax is enlarged as it recedes from the axis, and at its broadest part 

 makes an abrupt geniculation, turning almost rectangularly backwards, is pro- 

 longed into sharp spines in a direction p:irallel to the axis and extending beyond 

 the pygidium. The axis of the pygidium is marked by three rings, while the lateral 

 lobes are apparently smooth ( in one specimen), and the entire form is semiellipti- 

 cal, the axis obtuse at its posterior extremity, and bordered by a smooth extension 

 of the crust from the lateral lobes; which is in strong contrast with the preceding 

 genus. Nor can it be properly placed under Peltura, which has twelve segments 

 of th3 thorax, the cephalic shield not ext.nded in the posterior limb, nor the last 

 segment of the thorax produced as in the present form; while the pygidium is 

 emarginate at the extremity, and dentate on the margins. 



While the glabella has the form of Olenus, and the general form of the cephalic 

 shield corresponds to that genus, the extension of the last segment of the body in 

 spines parallel to the axis is a character of the typical species of Paradoxides 

 (see P. hohemiensis) : the pygidium is also much more nearly of the type of 

 Paradoxides, than of Olenus or Peltura. 



I propose therefore to designate this form by the generic name Bathtnotus. 



GENUS BATHYNOTUS (n.g.). 



[ Gr. j3a6vg, amplus, and vcjto^, dorsum ; in allusion to the ample central lobe or axis 

 of the typical species.] 



General form elongate ovate, distinctly trilobate. Cephalic shield somewhat 

 semielliptical, with the posterior angles prolonged in spiniform processes : po- 

 * This and the preceding species were published as Olenus thompsoni and 0. vermontana, 



in the Twelfth Annual Report of the Regents of the University on the State Cabinet of Natural 



History, pp. 69 & 60. 



