'iO RKV. N. ABRAHAM ON THE [Jail. 18, 



Fig. 22. The brain from the ventral aspect, nat. size. 



23. The roots ol' the 5th, 7lh, and Sth nerves, from the left side, nat. size. 

 Eefercnccs to Figs. 20-23. — a, elevation on inner wall of prosoca?le ; aula, 

 remains of the cavity of the unpaired cerebral vesicle ; b, elevation on floor of 

 prosocoele ; b.opt, basi-opticus ( = ventral portion of mesencephalon); ch.plx, 

 choroid plexus; dien, diencephalon ( = thalaniencephalon) ; di.cce, diacoele 

 ( = third ventricle); f^JC?;, epenceiDhalou (cerebellum); for.M, foramen of 

 Monro ; J/i/p, hypophysis cerebri ; mcs.cm, mesoccele ; yneten, metencephalon 

 ( = medulla oblongata) ; mt.cce, metacoele ( = fourth ventricle) ; opUn, optence- 

 phala ( = ojjtic lobes) ; /jtoaym, prosencephala (= cerebral hemispheres), united 

 into a single cerebrum ; prs.cce, prosoccele ( = lateral ventricle) ; rhinen, rliinen- 

 cephalon ; rJt.cce, rhinocale; tel.vasc, tela vasculosa ; vtl.iut, velum interpositum ; 

 i.-x., cerebral nerves. 



Plate VIII. 

 Carcharodon rondelctii (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.hr. 2, b.br. 5, basibranchial of the 2nd and Sth arches ; 

 h.br. 2, h.br. 4, hypubranchials ; c.hy, 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, X5. 



29. The brain from the dorsal aspect, nat. size. 



3. On the Habits of the Tree Trapdoor Spider of Graham's 

 Town\ By the Rev. Nendick Abraham. 



[Eeceived November 15, 1886.] 



Among the very numerous species of Arachnida which are fouud 

 through the Caje Colony there are several kinds of Trapdoor 

 Spiders. There is a species which, for convenience, I have called the 

 Tree Trapdoor Spider, ahout which I wish to give some notes. I 

 have been unable to tind any mention of this particular Spider in 

 any of my 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 ; but 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 thau others, though the trees chosen are various, but in 

 each case the trees have a rough bark. The house is a very wonder- 

 ful structure, though small, measuring not more thau one and a half 



1 Communicated by Dr. A. Giinther, F.E.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) xri. p. 310, pi. x. 1875). 



