292 S. H. SCUDDER OX NEW TYPES 



plate. The whole surface of the body upon both sides, as it lies coiled in an open spiral, is 

 covered with a thick mat of rather fine hairs which appear to be two or three times longer 

 than the diameter of the body. Two or three pairs of short and slender tapering legs can 

 be seen (not given on the plate) depending from the anterior segments; they are scarcely 

 half as long as the diameter of the segments. The length of the fossil if unrolled would 

 be 20 mm. ; its greatest diameter is 2.1 mm. The specimen is from the nodules of Mazon 

 Creek and was obtained by Mr. P. A. Armstrong. 



Trichiulus nodulosus, nov. sp. 

 PL 27, figs. 1, 3. 



Two specimens at hand are referred to this species, though each is so fragmentary that 

 the determination is uncertain. 



One o.f them (pi. 27, fig. 1) represents a dozen segments of the entire width of the crea- 

 ture, being apparently only a fragment of the larger end ; it does not taper, and the seg- 

 ments are about four times as broad as long, each furnished with two transverse series of 

 equidistant, small, rounded warts, apparently the bases for appendages of some sort ; the 

 series are also equidistant so that the warts are sprinkled over the surface in a xery regu- 

 lar fashion, like a checkerboard, in both longitudinal and transverse rows. Each series 

 on the same segment is separated from the other by a transverse depression a little 

 shallower than the sulcation between the segments. The warts are about 1.25 mm. dis- 

 taut from each other and slightly less than half a millimeter in diameter. The length of 

 the fragment is 29 mm., and its breadth 9.25 mm. No appendages of any sort are to be 

 seen; but next the margin in some places are faint signs of delicate hairs, and the discol- 

 oration of the skin in the neighborhood may indicate its previous extent. 



The other specimen (pi. 27, fig. 3) is longer, but by the method of preservation and the 

 cleavage of the nodule it only shows a portion of the breadth, and neither edge, so that no 

 appendages can be seen, nor any hairs. The same arrangement of warts or tubercles can 

 be seen, rendering it probable that it belongs to the same species as the other. These 

 wartlets are at the same distance apart as in the other specimens, and the series are simi- 

 larly arranged, the sulcations between the segments being slightly deeper than those 

 between the transverse series of a single segment; but the wartlets appear a little sharper 

 or more conical. The length of the fragment is 4-3 mm. and its extreme breadth 4.5 mm. ; 

 the segments can only be faintly seen over a portion of the fragment, but there were prob- 

 ably about twenty in this piece, which does not seem to reach either extremity. Both 

 specimens are from Mazon Creek and were obtained by Mr. P. A. Armstrong, and are in 

 his collection. 



Trichiulus ammonitiformis. nov. sp. 



PL 27, fig. 4. 



Although the single specimen found presents few tangible characters, it differs so much 

 from the others that it seems worth while to make it public. It is of much greater size 

 and is coiled into a slightly open spiral, and being preserved on a side view has a cursory 

 resemblance on the stone to a fossil ammonite. If unrolled it would measure about 115 



