new “Worm” from Lower Ludlow Beds. 129 
they do, and as we cannot class them anywhere else, we leave 
them where others have placed them.” 
The question remains: What sort of “ Annelida”? ? Most 
fossil worms are referred to the Cheetopoda. But if they are 
not T'ubicola, then they should show cliete or parapodia, and 
one would expect some cephalization or other differentiation 
into body-regions, such as occurs even in the somewhat similar 
Capitellide. The fossil called Protoscolew is not a tube either 
built or secreted, but must be the imprint of the actual in- 
tegument, It shows no trace of cheete or parapodia, and 
there is no other reason for referring it to the Polycheta. 
Whether the segmentation is complete or whether it is con- 
fined to the integument cannot at present be decided; the 
segmented appearance of the gut is capable of both interpre- 
tations. The straight simplicity of the gut excludes the 
Gephyrea, some of which present a superficial resemblance in 
the distribution of epidermal papillz, and in a tendency to 
calcification as expressed in the calcareous plates of some 
Sipunculids. My colleague, Mr. H. A. Baylis, has tenta- 
tively suggested comparison with a Nematode, and tells me 
that two genera of recent Nematoda have backwardly-pointing 
spines on the hinder edge of the cuticular rings. That, 
however, is no great resemblance, and the creatures in question 
are parasitic. Protoscolea also bears some likeness to mille- 
pedes ; but none of the fossils has shown any trace of ap- 
pendages, and the segmentation is much closer than in any 
known millepede. 
It is to the Oligocheta that Protoscolex presents thie 
strongest resemblance. ‘The general shape, the close and 
undifferentiated annulation, and the Jong simple gut are all 
suggestive of thatorder. ‘The apparent absence of a clitellum 
is by no means fatal, for that structure is less differentiated 
in the lower Oligocheta, is very slightly developed in the 
primitive Moniligaster, and in most aquatic Oligochzta appears 
only periodically. Therefore in Protoscolew it may not have 
reached such a stage of evolution as to be discernible in the 
fossils, or the animals may have perished out of the breeding- 
scason. -‘The very fine sete of the Oligocheta would, of 
course, be invisible in any fossil of this kind and size. It is, 
however, legitimate te suggest that the papille of certain 
species stood in some relation to sete: either they bore one 
apiece, or they represent the incipient stages of setxz. In the 
aduit of modern oligocheetes the setee are chitinoid rods 
embedded in invaginations of the epidermis ; but they first 
appear as small cones of chitinoid substance, growing first at 
Ann. & Mag. N. Hist. Ser. 9. Vol. v. 9 
