Br. S. Woodward — Neiv Pakeozoic Phyllopod Crustaceans. 387 



(if entire) have measured fully 65 mm. in length and 40 mm. in 

 breadth. We have only the anterior portion of this shield, but it 

 shows, that in such aged specimens, the fine radiating striae extended 

 forwards as well as towards the posterior border. 



Fig. 3 supplies exactly the portion of a large shield which is 

 wanting in Fig. 1. The two series of striae upon this specimen are 

 beautifully preserved as impressions on the shale, although the 

 black layer is absent. The concentric stride bend slightly upwards 

 on the posterior dorsal line. This specimen, when entire, must 

 have measured 50 mm. in length and 30 mm. in greatest breadth. 



Figs. 4, 5, 6, and 7 present in miniature all the characters of 

 Fig. 1, and might be disposed of at once, as young examples of 

 C. Bcemeri, but Fig. 5 deserves special notice. 



In this little specimen the V-shaped cephalic portion, so frequently 

 absent in the shields of these phyllopods, is here preserved in situ. 



The question very naturally arises, why is the cephalic portion 

 nearly always separated from the rest of the carapace ? If we 

 carefully examine the anatomy of specimens of the existing Aims, 

 Lepidiirus, or Nebalia, we shall find the answer very readily. The 

 fact is, the muscles of the natatory antennae, the maxillas, and maxil- 

 lipeds in these Phyllopod Crustaceans, all have their attachment to 

 the anterior portion of the cephalic shield, and in the process of 

 decomposition, after death, the carapace appears usually to have 

 separated along the cephalic suture; the anterior part, with the 

 appendages, being entombed in one spot, and the expanded posterior 

 shield-shaped portion floated to another-.^ 



When occasionally found together, as in Ceratiocaris papilio, Salter, 

 from the Upper Silui'ian of Lesmahagow, Lanarkshire (see Annals 

 and Mag. Nat. Hist., March, 1860, p. 154), the body is often so 

 twisted about in relation to the shield-shaped carapace, that the 

 anterior end has more than once been described as the posterior, 

 and vice versa. I pointed this out also in reference to Dithyrocaris 

 tricornis of Scouler (see G-eol. Mag. 1873, YoL X. PL XVI. p. 482). 



2. Cardiocaris veneris, mihi, sp. no v. Plate IX. Figs. 8-12. 



Under this specific designation, I have grouped together five 

 carapaces, in which the cervical suture is less acute than in the 

 preceding species, and the anterior angles of the carapace are 

 rounded or obtuse, giving to these shields the traditional outline 

 of an heraldic heart, or the form which is supposed to represent 

 that organ on valentines. It is very difficult in this, as in the 

 preceding species, to determine the presence of a dorsal suture 

 dividing the shield into two equal halves. The surface of the 

 carapace, when closely examined, reveals the same concentric strige, 

 but not the fine radiating lines seen on the preceding species. 

 The relative proportions of breadth to length differ greatly in C. 



^ The carapace, wMch forms the suhject of Fig. 10, on our Plate, has the im- 

 pression of a Spirorbis having been attached to its surface after death. Others also 

 appear to bear scars of organisms having fixed upon them; probably "spat" of 

 Ostrese or other small mollusks. 



