32 ROYAL SœiETY OF CANADA 



Pygidium about one-quarter of the length of the thorax, suboval 

 transversely, being rounded backward at the anterior angles. Traversed 

 by three furrows, which are curved and pointed more and more back- 

 ward, A narrow border goes around the i)ygidium. 



Sculpture. — The test is minutely granulated. 



Size. — Length, là mm. Head-shield, length. 5 mm. Width of middle 

 piece at front, 3 mm., at the back. 6 mm. Length of thorax, 7 mm., 

 width scarcely 6 mm. Length of jjygidium, 2 mm., width, 4 mm. Bare. 



Notwithstanding the general resemblance of this species to B. Howelli, 

 of which it might be thought a larval form, it appears to the writer to be 

 an inde})endent species. Young examples of B. llouelU 22 mm. long 

 show no tendency to develop the appearance and proportions of B. 

 larva. If it were an early form of B. Howelli we would expect to find 

 the eye-lobe further from the glabella than in that species, but the con- 

 trary is the case. There is also a marked difference in the sculpturing 

 of the side lobes of the pygidium ; in B. Howelli a furrow marks the 

 suture between the somites, in B. pupa this furrow is entirely wanting. 



This species appears to hold the same relation to oidinary forms of 

 Bathyuriscus that Olenelloides, Peach, does to the ordinar}' types of 

 Olenellus (sens, strict.), in that it retains in maturity certain larval 

 characters which have disappeared from the adult form in other species 

 of the genus. These, for this species, are a long sti-aight eye-lobe, shoi*t 

 posterior extension of the dorsal suture, short pleune ; and pygidium of 

 few somites. 



A remarkable feature of this trilobite is that the posterior end of the 

 eye-lobe is turned outward, this character I do not remember to have 

 seen in an}' other trilobite, except Anopolinus. 



NEOLENUS, n. gen. 



The species which wo describe under this head are not those grouped 

 under Walcott's modification of Meck's genus Olenoides, and which he 

 afterwards divided into Olenoides and Zacanthoides, but are different 

 from either of these types. One of the distinctions is in the pleural 

 furrow. In Olenoides ( = Dorypyge ?) it is a straight, broad furrow 

 going out well to the extremity of the ]:ileura. In Zachanthoides it is 

 also a wide furrow, but it has a heavy shoulder in the middle at its con- 

 nection with the ring of the rachis. In this group (Neolinus) the furrow 

 is narrow and oblique, a sin Paradoxides. Jf one will take the trouble 

 to refer to the original description of Meek he will see that the possession 

 of a broad open furrow is hi.s main reason for separating Olenoides fiom 

 Paradoxide.H. It is manifest, therefore, that trilobites having a Pai-atlox- 

 ides-liko furrow cannot be included in Olenoides ( = Dorypyge ?) 



The species included in the new genus are clo.sely I'elated to Para- 

 bolina : they differ chiefly in having a longer pj'gium and shorter 



