[4]. The term which we proposed for this hypothetical ancestor of insects, “Leptus-like” or “Leptiform,” was an unfortunate one, since the name Leptus was originally given to the six-legged larva of a mite (Trombidium), the origin of the mites and other Arachnida being entirely different from that of the myriopods and insects.
[5]. Proc. Bost. Soc. Nat. Hist., xvi, 1873, p. 3.
[6]. American Naturalist, May, 1880, pp. 375, 376.
[7]. Zoologische Anzeiger, Bd. xx, 1897, pp. 125 and 129. He also states that Campodea resembles the myriopods, especially Geophilus, in the primitive band at first lying on the surface of the yolk, and in the absence of an amniotic cavity; also before hatching the abdomen is pressed against the thorax, as in myriopods.
[8]. “Scolopendrella has very remarkable antennæ; they may be compared each to a series of glass cups strung upon a delicate hyaline and extensible rod of uniform thickness throughout; so that, like the body of the creature, they shrink enormously when the animal is irritated or thrown into alcohol, and they then possess scarcely two-thirds the length they have in the fully extended condition, their cup-like joints being drawn close together, one within the other. Peripatus, Japyx, many (if not all) Homoptera, and the S. Asiatic relatives of our common Glomeris have all more or less extensible antennæ.” (Wood-Mason, Trans. Ent. Soc., London, 1879, p. 155.)
[9]. Lassaigne gave it the name of entomoline.
[10]. Miall and Denny ex Krukenberg; Kolbe gives the formula as C9H15NO6 or C18H15NO12. As the result of his recent researches, Krawkow (Zeits. Biol., xxix, 1892, p. 177) states that the chemical composition of chitin may prove to be somewhat variable.
[11]. On allowing portions of a locust, a piece of the integument of Limulus, a scorpion, and a myriopod to soak for a month in white potash, neither were dissolved or affected by the reagent.
[12]. We may add, while correcting the proofs of this book, that the important summary, by Uzel, of his work on the embryology of Campodea appears in the Zoologischer Anzeiger for July 5, 1897. He observes that the premandibular segment in the embryo is very distinct, and that the two projections arising from it persist in the adult. “Campodea is now the first example where these appendages are present in the sexually mature insect and function as constituents of the completed mouth parts. I propose for these hitherto overlooked structures the name of intercalary lobes.” They each form a slightly developed chitinous lobe covering a gap between the base of the labium and the fused external lobe and palpus of the first maxillæ (which are inclined near the labium) in place of the mandibles which have sunken inward. Uzel also homologizes these appendages with two similar projections (Höcker) observed in the embryo of Geophilus by Zograf to be situated in front of the mandibles. Heymons has also detected this segment in the embryo of Lepisma.
[13]. While these pages are still in type, we may add, in confirmation of this view, that Uzel states, from his researches on the embryology of Campodea, that the maxillary tergites of the embryo only slightly share in building up the tergal region (occiput) of the head, but that they form the genæ of the maxillary segments. (Zool. Anzeiger, July 5, 1897, p. 235.)