[MATTHEW] STUDIES ON CAMBRIAN FAUNAS SS 



Neolenus granulatus, n. sp. (PI. II, figs, la to c.) 



This compact species is larger and proportionately wider than the 

 preceding. The body is as wide as the head and thorax and one somite 

 of the pygidium. 



The middle piece of the head-shield is subtrapezoidal in form. The 

 glabella is wide, its length in the adult being only a sixth greater than 

 the width, and it extends quite to the marginal fold. It is rather flat 

 and carries three pairs of shallow furrows, equally spaced, arching back- 

 wards, and on some examples faintly traceable across the middle of the 

 glabella; a four furrow, just in front of the inner end of the ocular fillet, 

 is faintly discernable. The occipital furrow is shallow, but extends all 

 across ; the occipital ring is broad and tei'minates behind in a short stout 

 spine. The fixed cheek, omitting the part in front of the ocular fillet, is 

 sub-triangular; at the eye-lobe it is nearly as wide as half of the width 

 of the glabella, at the back it is nearly as wide as the glabella. The 

 ocular fillet is nearly parallel to the anterior marginal fold and is evenly 

 raised ; the eye-lobe is short, not prominent, and is opposite the space 

 between the first and second furi-ows of the glabella. The dorsal suture 

 goes directly forward from the eye, and backward arches outward nearly 

 to the genal angle, the proportion of the cords of its curves is I, 1, If. 



The movable cheek, from the dorsal suture to the tip of the spine, is 

 nearly four times as long as wide ; the ai-ea at the eye-lobe is nearly twice as 

 wide as the marginal fold. The stout genal spine is about one-quarter 

 of the length of the cheek, and reaches across the three first segments of 

 the thorax. 



A hypostome which, from its great comparative width, it is thought 

 may belong to this species, has the following characters : The doubleur 

 is attached to the front and is narrowed towai'd the ends. The body of 

 the hypostome is subquadrate, has two short ears at each side, and a 

 marginal fold at the back ; the anterior lobe is nearly circular, and is sur- 

 I'ounded by a furrow. The posterior lobe is crescentic, and extends 

 around to the posterior of the two ears at the sides. 



The thorax consists of seven segments ; its length is equal to that of 

 the head-shield without the occipital ring. The rachis is broad, and each 

 ring bears a short stout spine at the back. The pleurae are flat and have 

 the tips bent abruptly backward ; the anterior ones are, inside the geni- 

 culation, about four-fifths of the length of the ring, the posterior ones are 

 equal in length to the ring ; the spines are about two-fifths of the length 

 of the pleurae. The first pleura seems to have no spine. 



The pygidium exclusive of its spines is as long as six segments of the 

 thorax, and is twice as wide as it is long. It bears five pairs of spines, 

 directed backward, those at the back being quite short. The rachis has 



