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Show 40 REV. N. ABRAHAM ON THE [Jail. 18, Fig. 22. The brain from the ventral aspect, nat. size. 23. The roots of the 5th, 7th, and 8th nerves, from the left side, nat. size. Eeferences to Figs. 20-23.-a, elevation on inner wall of prosoccele ; aula, remains of the cavity of the unpaired cerebral vesicle ; b, elevation on floor of prosoccele; b.opt, basi-opticus (----ventral portion of mesencephalon); ch.plx, choroid plexus; dien, diencephalon ( = thalamencephalon); di.cce, diaccele ( = third ventricle); epen, epencephalon (cerebellum); for.M, foramen of Monro; hyp, hypophysis cerebri; mes.ca, mesoccele; meten, metencephalon (= medulla oblongata); mt.cce, metacoele ( = fourth ventricle) ; opten, optence-phala ( = optic lobes); prosen, prosencephala ( = cerebral hemispheres), united into a single cerebrum ; prs.cce, prosoccele ( = lateral ventricle) ; rhinen, rhinen-cephalon ; rh.cce, rhinocct'le; tel.vasc, tela vasculosa; vel.int, velum interpositum ; i.-x., cerebral nerves. PLATE VIII. Carcharodon rondeletii (foetus). Fig. 24. The cranium from the dorsal aspect, nat. size. 25. The cranium from the ventral aspect, nat. size, font, fontanelle - a.s.c, p.s.c, h.s.c, elevations of the anterior, posterior, and horizontal semicircular canals ; h.m, facet for the hyomandibular. 26. Outer view of the right auditory capsule, nat. size, h.m, facet for the hyomandibular; h.s.c, elevation for the horizontal semicircular canal; spir.cart, spiracular cartilage. 27. The ventral region of the branchial skeleton, nat. size. b.hy, basi-hyal plate ; b.br. 2, b.br. 5, basibranchial of the 2nd and 5th arches ; h.br. 2, h.br. 4, hypobranchials; chy, ceratohyal; c.br. 1, c.br. 2, c.br. 5, ceratobranchials. 28. Posterior extremity of the vertebral column showing the last three true centra and the terminal demi-vertebra, X 5. 29. The brain from the dorsal aspect, nat. size. 3. On the Habits of the Tree Trapdoor Spider of Graham's Town1. By the Rev. NF.NDICK ABRAHAM. [Received November 15,1886.} Among the very numerous species of Arachnida which are found through the Cape Colony there are several kinds of Trapdoor Spiders. There is a species which, for convenience, I have called tbe Tree Trapdoor Spider, about which I wish to give some notes. I have been unable to find any mention of this particular Spider in any of m y books, or in any I have access to, and it has been until now unknown to our local or colonial naturalists, so far as I have been able to learn. Thinking it may be known to this Society, I have not presumed to name it; hut having very carefully observed for many months this wonderful creature, I send you these notes. Unlike other Trapdoor Spiders, these build their houses in trees- There are certain trees which are more favourable for building-purposes than others, though the trees chosen are various, but in each case the trees have a rough bark. The house is a very wonderful structure, though small, measuring not more than one and a half 1 Communicated by Dr. A. Gunther, F.R.S., V.P.Z.S., who stated that the Spider in question appeared to be Moggridgia dyeri (O. P. Cambridge, Ann. & Mag. Nat. Hist. (4) xvi. p. 319, pl. x. 1875). |