140 HALF-AN-HOUR AT THE MICROSCOPE. 



extend the limbs, noting their relative lengths, which measure with 

 a pair of compasses, and finely divided scale. If a male, the 

 palpi, and form etc. of the palpal organs must be specially observed. 

 The colour, markings, pubescence, with anything else that may 

 seem likely to help in the determination, must also be noted, and 

 then with the help of Mr, Blackwall's work, in which all are 

 figured of which specimens could be obtained at the date of 

 publication, the determination will generally be found tolerably easy. 



The eyes here stamp the specimen as belonging to the 

 EpeiridcE. The length and slenderness of the limbs bespeak it as 

 no other than Tetrag7iatha, which is confirmed by the character of 

 the claws, the falces, the mandibles, lip, and sternum ; form of 

 abdomen and colour are, it must be said, as a matter of course 

 lost. The palpal organs differ so much in their appearance when 

 made transparent from what they do in their living or recently 

 dead state, that one can only say, so far as characters can be 

 gleaned from them, they confirm the previous determination. I 

 may point out, as microscopically interesting, the remarkable 

 clearness of the openings in the fangs for exit of poison, the sac 

 for storing which may be seen on the right fang (left as mounted, 

 it being presented on its back) ; the striation of the muscular 

 fibre in the falces, the small size of the abductor, as compared 

 with the abductor muscle, the meaning of which will be apparent 

 on considering their uses ; the beautiful fringe of teeth on the 

 anterior edge of the maxillae \ compare these with the teeth of the 

 leech, shown in T. D. A.'s interesting slide. 



I never before saw so clearly what must be the action of the 

 maxillae in a spider of cutting, like the scarifier used in Cupping, 

 into the soft body of their prey. The juices as they flow on are 

 pressed out, being absorbed by the fringes of hairs, as a sponge, 

 whence they are drawn by suction into the body of the spider ; these 

 hairs having (from analogy, we may say with certainty) tasting 

 powers as well. 



The horny oesophagus and stomach are also well shown, and 

 (if I mistake not) nerves going to supply the limbs and viscera. 

 The beautiful " fluting,^' or spiral grooving of the spines, the slight 

 serration of the ordinary hairs, guards to the softer parts^ the tactile 

 hairs to warn of danger, softer, and standing boldly out almost at 

 right angles to the limbs, and the varying modes of implantation 

 of these respectively : all are points worthy careful study. It only 

 remains to mention the beautiful structure of the claws for combing 

 the creature's body and its lines, and the sustentacula, claw-like 

 hairs seated beneath the claws proper, to enable the creature to 

 hold on for hours in the inverted position without muscular effort 

 or fatigue, and we have the principal points shown by Mr. 

 Kingdon's capital specimen. 



