With regard to the differences between this species and _Ct. Sauvagii_, Latr. (_Ct. fodiens_, Walck.), size alone would suffice to distinguish them; two females of the latter now before me measuring 13 lines in length; while the male (_Aran. nouv. ou peu connus du Midi de l'Europe_, par Eugène Simon, Mém., Liège, 1873) measures 8 lines (17 mm.) and the female rather over 14 lines (30 mm.), the fore-central eyes in the female of _Ct. Sauvagii_ appeared to be smaller than those in _Ct. Moggridgii_ and placed rather farther forwards, but the eyes in both are otherwise remarkably similar both in size and position. The males, however, cannot be confounded inasmuch as, according to M. Simon, no trace of any transverse indentation on the caput exists in _Ct. Sauvagii_. The denticulation of the tarsal claws in the females of both species is similar, but M. Simon does not mention this portion of the structure of the male he describes of _Ct. Sauvagii_. The adult male of _Ct. Moggridgii_ above described, was found behind the stones of an old wall at Mentone, but not in any kind of nest. Nest-making, and excavating for that purpose, is, probably, no part of the work of the adult males in this and other allied genera, and hence we can see a reason for differences in the development of the caput, and the denticulation of the falces. The usual habitat of the females and their nests is in damp and shady spots, whereas _Ct. Sauvagii_ constructs its nests in dry exposed banks. _Habitat._ Mentone and San Remo. Cteniza Californica, sp. n., Plate XV., fig. B, p. 198. Adult female; length very nearly 14 lines; length of the cephalothorax, 5-1/2; greatest breadth of ditto, 5; breadth of fore part of caput, 4 lines; length of caput rather over 3 lines. The _cephalothorax_ of this spider is rather broader in proportion to its length than that of _Ct. Sauvagii_, Walck., Sim. = _Ct. fodiens_, Walck. The convexity, or elevation, of the caput is also less, but that of the thorax is greater, so that (when looked at in profile) the profile line of the two forms a tolerably even and continuous slope, interrupted only by the thoracic fovea; the profile, however, of the occiput is curved.