ANATOMICAL NOMENCLATURE. 



129 



Cym- 

 bium 



not proved, and it is possible that the male sometimes applies the genital 



bulbs to the sexual aperture, and thus charges them with the 

 of Sperm ^•^''^i^i^i^g fluid, a fact which Menge seems to suspect may be 



the case with Lycosa rurestris.' That tins transfer is so seldom 

 observed, and by so few persons, will not excite wonder on the part of one 

 who has devoted much time to the study of the habits of these reticent 

 creatures, and who knows the difficulty of obtaining a complete observation 

 of even the most common of its habits. Possibly the extrusion of the 

 sperma by the male upon the little silken receptacle from which it is 

 absorbed into the palps takes place very rapidly ; or it may be done long 

 before the act of fertilization ; perhaps, as Thorell suggests, immediately 

 after the last change of the skin. 



The.Cymbium is that part of the modified digital joint of the male 

 spider's palpus upon which is placed the copulatory apparatus which it 



sustains. In many species of Orbweavers it covers one side of 



the digital, having 



tlie appearance of the 

 half of a seed husk, or shell of 

 grain, and is covered more or 

 less thickly with hairs and 

 bristles. (See Fig. 98, cym.) 

 The alveolus (alv) is the 

 concavity in the cymbium 

 within which is located the 

 copulatory apparatus proper. 

 Its form depends upon the 

 structure of the cymbium, with 



certain spiders oeeu- 

 Alveolus. . 1 ,j, J. ^, 



pying half of tJie sur- 

 face, in which case the cym- 

 bium has the form of a canoe. 

 With others it is smaller, as 

 with Segestria, for example ; 

 with others again larger and 

 occupying the whole surface of the cymbium. The simpler the structure 

 of the apparatus the less is the alveolus in circumference and depth, and 

 vice versa. The more complicated is the apparatus the more space it 

 embraces in every sense. 



The alveolus serves as a seat for the Hismatodocha (haem), a foUicule 

 placed in the form of a spiral, and intended with some spiders to* serve 

 as a seat for the copulatory apparatus itself. The alveolus has no inde- 

 pendent significance ; its form and size in its development are dependent 



gia.d.. 



VI. 



or.haen- 



Fig. 98. Digital joint of palp of a male spider (after Wagnerl, 

 schematic longitudinal section of the cymbium with the copu- 

 latory apparatus drawn out; erab. embolus; teg, tegulum; 

 mea.san, meati sanguinis, minute ducts for conducting blood 

 from the hamatodocha (hsemi into the receptaculum semi- 

 nis, rec.sem ; the arrows indicate the course of the blood ; 

 gla.cl, glandular cells ; alv, the alveolus or hollow of the cym- 

 bium in which the apparatus rests. 



' Lebensweise d. Arach., page 43. 



