628 



SIMIAN IA 



used H- food. Tlir leaf-cells have a spiral structure 

 anil large pores in their Hides. See MOSSES; and 

 Braithwaite's Sf^OfftUUtU (1880). 



Splmkia, a small \*ni (|ni|i. 600) on the south 

 coast of Crete, 60 miles SE. of Canea. The name 

 of Sphakiota is, however, given to all the high- 

 landers in the mountains to the north, always dis- 

 tinguished for their bravery in anti-Turkish risings. 



Sphene. See TITANIUM. 



SplM'iiodon. "i HATTERlA.the representativeof 



a distinct reptilian order Khynchocephalia which 



in IVi iniaii and Triassic times included several 



. genera. Now there is only one species Spkenodon, 



or perhaps better Hatteria, punctata the Tuatara 



Fig. 1.- 



( Hatttria pu 



of the Maoris. It was formerly abundant along 

 the coasts of New Zealand, but is now restricted 

 to a few small islands in the Bay of Plenty, both 

 the Maoris and the hogs being blamed for its 

 rapidly increasing rarity. In all likelihood it will 

 soon lie exterminated, and one of the most interest- 

 ing of ' living fossils' will be lost. 



In appearance the Hatteria is like an Iguana ; 

 on the upper surface the general colour is 'dull 

 olive-green spotted with yellow,' on the under sur- 

 face whitish ; the tail is compressed from side to 

 side and dorsally crested, brittle and replaceable 

 a- in many of tlie genuine lizards. The maximum 

 length of the animal seems to lie about two feet, 

 lnit -mailer forms are commoner. Nocturnal in its 



habits, the Hatteria 

 lives in holes among 

 the rooks or in small 

 burrows, and feeds 

 on small animals. 



But the chief pecu- 

 liarities of this old- 

 fashioned reptile are 

 internal, aim cannot 

 be suited except in 

 technical language. 

 The vertebra are Li- 

 concave like those of 

 most fishes, as is also 

 the case in geckos 

 among li/arda and in 

 many extinct reptiles. 

 Some of the ribs bear 

 nnoinate jinx-esses as 

 in birds and croco- 

 diles. As in no.-,, 

 diles there arc 'ab- 

 dominal rilw," or ossi- 

 fications in the fibrous 

 tissue iMMio.ath the 

 skin of the abdomen. 

 The skull, unlike 

 that of any lizard, ban an ossified quadrato-jugal, 

 and therefore a complete infra-temporal arcade ; 



- 



-9 



h 



Fi,;. l!. Section of Pineal Eye 

 of Hktteria Ufter Baldwin 

 Spencer ) : 



, a comii-ctivr-tlMiie capsule he- 

 nth the iikln; l>. tl' Ifiw ; r. 

 thf cavity of tin- cy : rf, t. layern 

 nf the rctinm; / bloorf-veweU ; 

 (7, , Ulk. 



the quadrate is immovably united to pterygoid, 

 squamosal, and quadrato-jugal ; the pterygoids 

 meet the vomer and separate the palatines. 'There 

 are teeth on the palatine in a single longitudinal 

 row, parallel with those mi maxilla and mandible, 

 and the three set- seem to wear one another away ; 

 there is also a single tooth on each side of a sort of 

 beak formed from the premaxilla'. 



It was in Hatteria first that Baldwin Spem-er 

 discovered what seems to be the secret of the 

 pineal body. This structure occurs in all Verte- 

 brates, except the very lowest, at the end of an 

 upgrowth from the 'tween brain or optic thalami. 

 It- import remained for long an enigma. But in 

 Hatteria the pineal body reaches the skin on the 

 top of the head, and retains distinct traces of an 

 eye like structure for instance a complex retina. 

 As the same vestigial hint of eye-structure has 

 since been seen in several lizards, many naturalists 

 are confident that the pineal body should be called 

 a pineal or parietal eye, and regarded as a per- 

 sistent vestige of a median, unpaired, upwonl- 

 looking sense-organ. See PINEAL GLAND. 



Near the living Hatteria the Permian Paliro- 

 hatteria, the Triossic Hyperodapeton, and some 

 other important extinct types must be ranked. 

 Nearly allied too is the remarkable Proterosaurus 

 from the Permian. There is no doubt that the 

 order Khvnchocephalia once included several 

 generalised types, of which Hatteria now alone 

 remains. It is much to be desired that the develop- 

 ment of this animal be studied before it also dis- 

 appears. 



Sphenoid Bone. See SKULL. 



Sphere, a surface of which every point to 

 equally distant from a definite point known as the 

 centre. It may be descrilied by the rotation of a 

 semicircle (or circle) about its diameter. From 

 every aspect a sphere has the same appearance. 

 Every plane section is a circle a great circle if 

 the cutting plane contains the centre of the sphere, 

 a small circle in all other cases. The shortest line 

 that can be drawn on the surface so as to join any 

 two points must be an arc of the great circle pass- 

 ing through these t\vo points. Jf r is the radius 

 of the sphere its volume is JUT* and its surface is 

 4-rr 1 . These are intimately related to the volume 

 and curved portion of the surface of the circuin 

 scribing cylinder, whose height is equal to the 

 diameter of the sphere. The volumes are as two to 

 three, and the surface areas, so defined, are equal. 



Spheroid* are species of Ellipsoids (q.v.), and 

 are represented by the same equation. If an ellipse 

 be made to revolve round one of its axes, thecnned 

 outline of the ellipse describes the spheroid. Should 

 the major or longer axis be the axis of revolution 

 the spheroid is said to berota<, but if the minor 

 or shorter axis, o/i/ate. The Earth (q.v.) is very 

 approximately on oblate spheroid. 



Spheromcter is an instrument for measuring the 

 Npherieity of portions of spherical Mil faces for 

 example, lenses. It rests on throe pointed legs, 

 whose points form an equilateral triangle. Mid- 

 way between these is a fo.urth leg, which can be 

 screwed up or down as desired through a distance 

 measured by the number of turns given to it. After 

 the sphoiomotcr is adjusted on any spherical surface 

 till the four legs arc all in contact with the surface 

 it is lifted on to a plane surface and the middle 

 leg screwed up or down until the four legs all lie 

 on the plane. Thus we measure the bright of the 

 segment whose base is the circle passing through 

 the equilateral triangle mentioned ol>ove, and e;m 

 by a simple calculation find the radius of the 

 spherical surface. The instrument may also be 

 applied to measure the thicknesses of plates small 

 enough to he pushed within the legs. 



