"Observation. The difference which distinguishes our _Mygale_ from the _Sauvagesii_ consists, first, in the toothing of the mandibles, which is observable on one side only of the channel, and not on both; secondly, in the tarsi all equally armed with spines, and not only the four anterior ones; thirdly, in the colour of the thorax and the abdomen, which is not uniform as is usual in the _Sauvagesii_. Nevertheless, such differences might be in part climatic, which would cause our _Mygale_ to be considered as a mere variety of the same species, and the others might be the result of the different method of examining the parts, and of the goodness of the instruments." At p. 19, in the _Fauna del Regno di Napoli_, M. Costa gives the following account of the nest of _Nemesia cellicola_, which he discovered above San Martino in September, 1833:-- "Vive entro la polvere arida, nelle cavità oscure delle muraglie, e propriamente nelle così dette _Saettiere_, ove, col glutine suo, si costruisce un tubo delicato e mobile, che ha cura di affidare nel suo origine a qualche corpo stabile nel fondo del muro, e che in terra nella polvere, aprendosi l'altro estremo sul piano inclinato dalla polvere stessa costituto." This, with the exception of the words "e che in terra nella polvere," which are unintelligible to me as they stand, and appear to want a verb, may be translated as follows:-- "She lives in the dry dust, in the obscure crevices of walls, and especially in those which are called _Saettiere_ (loop-holed walls?), where she constructs a delicate and flexible tube with her viscid secretion, and which she takes care to fasten at its commencement to some solid body at the bottom of the wall, ... the other extremity opening on the inclined plane formed by the dust itself." We may remark that there is here no mention of any door or concealment at the mouth of the tube, and in this and some other respects the nest of _Nemesia cellicola_ would appear to resemble the nest of _Atypus piceus_ from the neighbourhood of Paris. See above in the text, p. 78. B. _On the Habits of Cteniza Ariana._ The following is a free translation of an account read by M. Erber before the Botanico Zoological Association of Vienna,[98] of the very curious observations which he made on _Cteniza Ariana_ when travelling in the Grecian Archipelago. [Footnote 98: Verhand. der k. k. zoologisch-botanischer Verein in Wien, vol. xviii. (1868), p. 905.] "On my return voyage [from Rhodes], I stayed for a fortnight in the island of Tinos, and, among other things, I captured several specimens of the so-called trap-door spider (Deckelspinne) _Cteniza Ariana_, Walck., and with much trouble procured an entire tube and trap-door of this creature.... I am thus enabled to exhibit to this honourable assembly the complete nest of this creature, and the spider herself, with her eggs, preserved in alcohol, and can moreover add some few words as to her habits.