new "JVorm" from Loioer Ludlow Beds. 129 



tliey do, and as we cannot class tliem anywhere else, we leave 

 til em where others have placed them." 



The question remains : What sort of " Annelida " ? Most 

 fossil worms are referred to the Chaitopoda. But if they are 

 not Tubicola, then they should show chjBtse or parapodia, and 

 one would expect some cephalization or other differentiation 

 into body-regions, sucdi as occurs even in the s)mewhat similar 

 Capitellida3. The fossil called Protoscole.v is not a tube either 

 built or secreted, but must be the imprint of the actual in- 

 tegument. It shows no trace of chpetjB or parapodia, and 

 there is no other reason for referring it to the Folychaita. 

 Whether the segmentafion is complete or whctiier 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 papillpe, and in a tendency to 

 calcification as expressed in the calcareous plates of some 

 Sipunculids. My colleague, Mr. H. A. Baylis, has tenta- 

 tivily suggested comparison with a Nematode, and tells me 

 that two genera of recent Nematoda have backwardly-poiming 

 S))ines on the hinder edge of the cuticular rings. That, 

 however, is no great resemblance, and the creatures in question 

 are parasitic. Protoscolex 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 OligochsBta that Protoscolex presents the 

 strongest resemblance. The general shape, the close and 

 undifferentiated annulation, and the long simple gut arc all 

 suggestive of that order. The apparent absence of a clitellum 

 is by no means fatal, for that structure is less dill'erentialed 

 iji the lower Oligochajta, is very slightly developed in the 

 primitive Moniligasttr, and in most aquatic Oligochaita appears 

 only periodically. Therefore in Protoscolex 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- 

 siason. The very fine seta; of the Oiigochaita would, of 

 course, be invisible in any fossil of this kuid and size. It is, 

 however, legitimate to suggest that the papillie of certain 

 species stood in some relation to seta3 : either they bore one 

 apiece, or they represent the incipient stages of setie. In the 

 adult of modern oligocha2tes the setaj are chitinoid roils 

 enibelded in invaj^inations of the epidermis ; but tln-y first 

 appear as small cones of chitinoid substance, growing liist at 

 Ann. ik Mug. N. Hist, fcicr. 9. Vol. v. i> 



