SALTEK PELTOCARIS. 



89 



short space across the vertical lines on the general surface (just as 

 these are continued also faintly towards the margin). The vertical 

 lines, though more distant than the marginal ones, are still very 

 close together — eight or nine of them at least in the space of pg-th of 

 an inch. They are not so regular as they appear to be at first sight. 

 Most of them, after proceeding a short distance, turn obliquely and 

 abruptly forwards, or else are crossed by short oblique striations, to 

 join the next vertical line, which is generally, but not always, obli- 

 terated above the point of junction (as at a). Very rarely these 

 oblique lines cross the space of two vertical lines (6) ; and, as they 

 are all strictly in the same direction, they give the appearance of a 

 third set of parallel stria? ruled across the other two. 



Fig. 2. — Peltocaris ? HarTcnessi. A, natural size. B, enlarged. 



The faint transverse lines above mentioned are, I believe, due to 

 mineralization only ; but three sets of lines are certainly present, viz. 

 the strong, vertical ones, the oblique, close, marginal striae, and, lastly, 

 the short, oblique lines in the opposite direction to those last mentioned. 

 I do not remember such a complication of lines on the surface of any 

 other carapace*. Peltocaris aptychoidesis so small and smooth, that 

 there is no opportunity of judging whether it may be the young state of 

 this larger species. Its nearly uniform size in the half-dozen speci- 

 mens I have seen would seem to be in favour of its being distinct. 



Locality. Anthracite-beds (Llandeilo-flags), Dumfriesshire. Pro- 

 fessor Harkness's collection. 



And now a word or two regarding the affinities of this curious 

 Crustacean. 



Before the structure of Ceratiocaris was known, of which genus a 

 reduced figure is here given (fig. 6), the rostral portion of Peltocaris 

 could not have been understood. But a reference to the accom- 

 panying series of woodcuts will show that a tolerably broad rostrum, 

 placed in the same relative position, occurs in Ceratiocarisf. In the 

 recent Nebalia (fig. 12) it is fixed ; and in Dithyrocaris (fig. 8) and 



* The margin of Argas testudineus (fig. 9) is striated, but in the same direction 

 as the transverse lines on the rest of the shield. 



f More complete figures are giyen in the Ann. & Mag. Nat. Hist, for March 

 1860, p. 154. 



