NEW AUSTEALIAN SPH^jaOMID. 147 



tliat of the sixth segment of Campecopea Mrsuta ; but it does not 

 extend over more than half the tail, and is rather thinner in the 

 middle than at the end, which has a slightly nasal or trilobed ap- 

 pearance. On either side midway between this central trunk 

 and the flanks, this seventh segment is armed with a small tooth 

 on the hind border, both border and trunk being more or less 

 scabrous. The pleon, or tail, is convex, with two curves — the first 

 showing three lines of segmentation, the second, and larger, con- 

 stituting the terminal tail-segment. This is granulated, and bears 

 two small serrated elevations commencing at the base and scarcely 

 extending beyond the process of the seventh body-segment above 

 described, immediately under which they lie. Between these 

 there is a shallow depression in the convexity of the tail, conti- 

 nuing, indeed, beyond them, but becoming shallower and almost 

 imperceptible. At the base of the terminal tail-segment a deep 

 socket receives the apparently immovable articulation of the 

 inner tail-appendages. These lie close along the nearly straight 

 and somewhat flattened margins of the terminal segment, free 

 from, but fitted to, a very fine semicylindrical elevation upon the 

 margin. The end of the tail presents a rather broad, but very 

 shallow, excavation flanked by a small tooth on either side, while 

 from its centre projects the tooth mentioned above in the generic 

 description, to which the inner tail-appendages have every ap- 

 pearance of being firmly soldered. The tail-appendages them- 

 selves are curiously marked round their edges, the markings being 

 below the surface. The closely set lines of this border-venation 

 give off" two or three branchlets apiece, which run quite to the 

 margin. The outer plate is rather deeply concave above ; and 

 when the outer plates are folded as far as they will go Deneath 

 the inner, an appearance is presented of semicircle within semi- 

 circle, both the inner and the outer curve having a diameter greater 

 than the width of the body, which tapers slightly towards the 

 head. Having regard to this appearance, which makes the 

 animal very unlike the other members of the Sphreromid family, 

 the genus may be called Cyclura, with venosa for its specific desig- 

 nation, in allusion to the markings of the uropoda. 



It remains only to mention that the length is about half an 

 inch, and that the body-segments are armed on each side with a. 

 small projecting ridge which runs out into an angle or tooth 

 towards the tail. 



While introducing what appears to be a species of a new 



LINN. JOURN. ZOOLOGY, VOL. XII. li 



