ON THE FOSSIL PHYLLOPODA OF THK PALEOZOIC EOCKS. 231 



really the longest, or the true telson, but was one of the ' laterals ' or 

 ptylets. Hence the whole animal was probably much longer than our 

 former estimate made it. 



10. C. robusta, Salter (' Third Report,' p. 24), being based merely on 

 some small caudal appendages (Cambridge Museum a/925 and a/926) 

 without carapaces, is troublesome and unsatisfactory to deal with. We 

 find some equivalent styles and broad blade-like stylets, like long scalene 

 triangles, in G. papilio, stygia, acuminata, &c. ; but none of these seem 

 small enough for the several little sets of trifid appendages, more or less 

 perfect, which we have met with. C robusta takes in some of these ; but 

 Oxford Mas. T is relatively broad, and might be termed lata; B.M. 

 58878, from Muirkirk, has very narrow members {anyusta) ; and one set 

 in the Owens College is so neat, symmetrical, and small that it might be 

 called minuta. 



11. The specimens Ludlow Mns. S. and M.P.G. X-ji^^ jjave each a 

 long style and a strong stylet attached to a broken ultimate segment, 

 and were regarded as var. longa in the ' Third Report,' p. 25. Although 

 not showing the lattice-pattern so often seen on the segments of G. papUio 

 and G. stygia, they may well belong to one of those species, and the or- 

 nament may have flaked off from the ultimate segment. The study of 

 C. papilio and stygia (' Third Report,' pp. 16-20) we have not yet ex- 

 hausted by any means. We know, however, that the abdominal segments 

 were delicately sculptured with leaf-like or lattice-pattern ornament, the 

 points of the triangles pointing upwards, or rather backwards, towards 

 the carapace, and one limb of the triangle, where free, running downwards 

 and outwards in the other direction. These oblique lines are often visible 

 when the triangles have disappeared from wear or decomposition. Among 

 many others the segments M.P.G. X^Li; B.M. 41900: Oxford Mus. A 

 and H exhibit fine examples of this leaf-like ornament ; and it is visible in 

 several more complete individuals in those collections. In the Braidwood 

 and Glasgow Museums numerous specimens show it well. See also 

 'Third Report,' p. 31. 



12. A small and very delicate specimen, B.M. 59648, has a thin sub- 

 ovate carapace, with excessively fine parallel longitudinal stri®, and shows 

 14 or 15 segments, some within and five outside the carapace, ending with 

 a neat trifid set of appendages. This differs from any other form 

 we know ; and probably some small loose bodies, of numerous segments, 

 occurring in the Lesmahago shales (' Third Report,' p. 20) may be of the 

 same species. Its looseness of structure would suggest the name laxa. 



13. Of G. Salteriana, noticed as a new species in the ' Third Report,* 

 p. 23, we have not yet seen any additional specimens. 



14. The specimens which we referred to in the ' Third Report,' pp. 23 

 and 24, as C. cassia, Salter, are separable into two forms. G. cassia proper 

 is recognised on an interesting slab, of which one counterpart is in the 

 Ludlow Museum (E and F) and the other in the Museum of Practical 

 Geology ac Jerniyn Street, London (X|). The other somewhat similar, 

 but larger and otherwise different, specimens are not unlike in the 

 characters of the carapace, but they have more abdominal segments 

 exposed and proportionally longer caudal appendages — M.P.G. X^^J 

 B.M. 39400 ; Ludlow Mus. K ; Oxford Museum L and Q. These might 

 be conveniently named G. cassioides. 



In all the specimens of both kinds the carapace has been apparently 

 thin and tough, so as to allow of their being crumpled very much. This 



