88 AN ACCOUNT OF TWO NEW CRUSTACEA 



fig. 3). The number of genera hitherto described are 10, and of spe- 

 ecies 52. The specimen I now describe (see plate, figs. 2 — 3) seems to 

 combine the characters of Serolis, Limulus, AgnostuSj and Paradox- 

 oides, with others peculiar to itself. It is enclosed in an ironstone 

 nodule from Prior's Lee, in Shropshire, where the strata are far 

 richer in organic remains, both animal and vegetable, than the 

 Staffordshire coal basin, and it was from thence that Dr. Buckland's 

 Limulus was derived. Some vegetable remains are visible on the ex- 

 terior of the nodule. The accompanying figure is of the natural 

 size. The lime, as in most calcareous fossils enclosed in ironstone, 

 is in a crumbling powdery state, and is left white in the figure. 

 The antennae are very distinct, but the central anterior projection 

 is not clearly defined, although, like the antennae, it has a kind of 

 tubercle at its base. The ribs or plates, with their lateral prolong- 

 ations, are very evident ; the two anterior being connected by a 

 web into a kind of fin, which is readily distinguished from the pro- 

 longation of the shield observable in Limulus, Ogyges, and Para- 

 doxoides. The surface of the specimen, from which the lime has 

 crumbled away, is covered by minute crystals, and does not exhibit 

 the tuberculated appearance of the surface of the Trilobites. The 

 lateral projections are slightly grooved, and taper to a point. There 

 is no appearance of eyes in either of the two specimens I have seen, 

 unless the central projection is considered as such. The last of the 

 elevated dorsal segments is remarkably prominent, and is quite dis- 

 tinct from the tail. The number of segments is six, extended late- 

 rally into as many ribs, terminated by a like number of legs, or 

 more probably fin-rays or spines, for they exhibit no traces of a 

 jointed structure. 



Thus, in possessing antennae it resembled the Serolis ; it had a 

 tail and lateral spines like the Asaphus and Limulus ; its shape was 

 that of Agnostus — i. e. extended laterally, not lengthwise ; and it 

 was devoid of eyes like Paradoxoides ; which it also approached 

 in the extended points of its shield. Judging from a note of 

 Cuvier (Regne Animal, t. iv., p. 204), it closely resembles the de- 

 scription of the Paradoxoides of Rasoumowski. 



The figure, (No. 4), is taken from an imperfect specimen of the 

 shield of a crustaceous animal from the Dudley limestone. ' The 

 spine or antenna is very distinct, but the other parts, having been 

 much rubbed, are restored, as far as possible, from the cast. Its 

 shape is that of a rounded oblong, arched and mammillated, and 

 having an elevated margin ; the whole surface, except the antennae, 

 is covered with the same minute tubercles that are observed on the 



