874 R. ETTIERIDGE, JUX., OX THE OCCURRENCE OF A 



guiar ; but as the anterior part in front of the cervical furrow (d, 

 figs. 1 i 2) is much mutilated, it is difficult to speak with cer- 

 tainty on many essential points in its organization. The posterior 

 margin, which, on the other hand, is well denned, is concave in 

 the median region, and the lateral angles apparently pointed 

 (/, fig. 3). The carapace was occupied in the median line by a 

 cephalic ridge (</, figs. 1, 2, 3), continuous from the cervical groove 

 to the posterior margin. I feel convinced that this was produced 

 anteriorly into a rostral ridge, perhaps slightly interrupted by the 

 cervical furrow, but to all intents and purposes forming a continua- 

 tion of the cephalic ridge. Placed at equal distances, on each side 

 of the latter, is a lateral ridge (7t, figs. 1, 2, & 3), nearer to it than 

 to the lateral margin (i, fig. 3) ; both these appear to commeoce 

 at the cephaliG groove, thence proceed backwards, as in the case of 

 the median ridge, and, like it, terminate at the posterior margin of 

 the carapace. So far as can be seen, the lateral margins of the cara- 

 pace are entire, without any trace of serration. In the specimen 

 seen in profile (figs. 1 & 2) the carapace is bent almost, but not 

 quite, along the median line, a little more on one side the median 

 ridge than on the other. Anterior to the cephalic groove the 

 fore part is so confused that no definite characters are traceable ; 

 still it is quite evident that appendages did exist, probably re- 

 presenting the antennae and antennules. In fig. 2, at Tc, there 

 is an indication of an appendage in what would be the position 

 of the antennae, which may, indeed, so far as we can judge from 

 the indistinct outline preserved, be the basal scale of one of them. 

 The cephalic groove itself (d, figs. 1, 2, & 3) is broadly V-shaped ; 

 and at it stop short the two lateral lines or ridges ; but the central 

 one is continued in front of it, and forms the rostrum (m, figs. 1 & 3). 

 No trace of eyes, either pedunculated or sessile, can be made out. 

 The abdominal somites, as before stated, are six in number, irre- 

 spective of the telson. They are narrow, and apparently possessed 

 pointed pleurae (I, figs. 1 & 2). The appendages, as preserved, are all 

 thoracic (c, figs. 1 & 2), and seven in number on each side ; at any rate 

 there are certainly six ; and I believe, seven. There is no appear- 

 ance of a division into endopodite and exopodite. The individual 

 seen in profile (figs. 1 & 2) demonstrates that the caudal appendages 

 were probably two on each side, or four in number (6, figs. 1 & 2). 

 Surface ornamentation is not discernible on any part of the specimen. 



4. Affixities and Systematic Position. 



Had the eyes been preserved, a difficulty which meets us at the 

 outset would be avoided, and the considerations as to the syste- 

 matic position of this interesting Crustacean much abbreviated. As 

 it is, we can only conjecture its relation to the Podophthalmata from 

 general analogy and the protection of the anterior portion of the 

 body by a carapace. If the presence of a well-defined carapace 

 without the actual observation of stalked eyes be accepted as suffi- 

 cient evidence of Podopthalmatous affinity, wo then have a choice of 



