76 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



semicircular, as wide as the abdomen, and as long as the last three 

 segments taken together. 



Amphipeltis paradoxus, spec. nov. Fig. 11. 



The length of the carapace is fully -| of an inch ; its breadth some- 

 what less. It is gently convex in the middle, and, if the appearance 

 be not deceptive, it has the central area subtriangular and raised 

 above the flattened sides. But I can see no trace of definite orna- 

 ment on the surface, nor any eyes. The margin shows a minute 

 serration. Beneath the carapace the thorax-rings, four in number, 

 are very narrow at their origin, but they attained their full width 

 before leaving the shield ; and the hinder seven rings are all about 

 i an inch broad, smooth, or with scattered punctations, and regularly 

 arched from side to side. The pleura are somewhat oblique, bent 

 backwards, and a little rounded at the tips; they are not distinguished, 

 except by the remote fulcral point, from the broad axis. 



Looking for the analogues of this fossil among recent forms, one 

 is obliged to neglect the whole of the Isopod order, on account of 

 the great size of the carapace in the fossil before us. This becomes 

 a point of agreement with the Phyllopoda, to some of the Apodoid 

 forms of which there is a general resemblance ; the few segments 

 of the body do not prove otherwise, since in the Palaeozoic forms of 

 the group (Ceratiocaris, &c.) the number is much less than in the 

 recent forms. But the expanded, broad shape of the segments is 

 unlike that of any Phyllopod. Again, although the recent Apus 

 productus has a large, spatulate, terminal joint (other species have a 

 short notched one), yet the great caudal styles are much more im- 

 portant than the telson. These styles, however, in the Palaeozoic 

 forms are always elongate, sometimes greatly so ; and hence, if 

 Amphipeltis be a Phyllopod, it is of a group yet unknown, and should 

 form the type of a new family. I should prefer comparing it (as Dr. 

 Dawson did in his letter to me) with the Stomapoda ; among these, 

 Squillerichthys and Erichthys have a large caudal shield, but their 

 carapace is both angular and spinose. I confess I am not at all 

 satisfied with this analogy, but consider it at all events preferable 

 to that of the Phyllopoda. 



Locality. Devonian rocks near St. John's. Fragments of a Fern 

 and of a Cardiocarpum occur here on the same slab of black glossy 

 slate. These plants have been described by Dr. Dawson, Quart. 

 Journ. Geol. Soc. vol. xviii. pp. 296, &c. 



Diplostyltjs, gen. nov. 



Carapace unknown. Body-segments (in number — ?) arched, and 

 with minute pleura. Tail-segment large, triangular, spinose, with 

 two pairs of simple, ovate appendages. 



It was not till I had tried hard to find analogies with Squilla that 

 I could persuade myself that this was not the abdomen and tail- flaps 

 of a Crustacean allied to that genus. The shape, ornaments, and 

 spines of the broad telson cannot fail to remind the observer of 

 Squilla (fig. 8); and if I could have believed that the palettes (fig. 6a) 



