The External Anatomy of Spidus 



bulb. In many cases the embolus is very long while the conductor is short; but 

 in every case the embolus in the unexpanded bulb occupies such a position that 

 its tip is protected by the conductor. 



In most cases the conductor can be recognized at a glance by its peculiar 

 texture; sometimes it is chitinized to a considerable extent, but even then it usually 

 has a membranous margin; and in any . a*e it can be recognized by its relation to 

 the tip of the embolus in the unexpanded bulb. 



The embolic subdivision. — Closely connected with the membranous base 

 of the conductor is the base of a separate subdivision of the apical division of 

 the bulb; as this portion bears the embolus it may be termed the embolic sub- 

 division. 



The radix and the stipes. — Immediately following the membranous neck that 

 connects the middle and the apical divisions of the bulb and parallel with the 

 membranous base of the conductor, there are two segments of the embolic sub- 

 division; to the basal one of these ! apply the term radix (Fig. 102, ra); and to 



the second, the term stipes (Fig. 102, 5/.). For 



con ,&** a more distinctly segmented condition of the 



base of the embolic subdivision see the figures 



emb. 



'-■ cynt. 



Fig. 103. PALPUS OF LINYPHIA 

 PIIRYGIANA 



Fig. 104. 

 PALPUS OF ARANEA FRONDOSA 



of Eriophora circulata given later (Fig. 109 and 1 10), where the corresponding parts 

 bear the same letters. 



The embolus. — The organ through which the ejaculatory duct opens, the 

 embolus, is comparatively simple in Linyphia, being a short spine-like part (Fig. 

 102, emb). 



The lateral subterminal apophysis. — In Linyphia phrygiana there is developed 

 a remarkable plate-like apophysis, which serves to protect the exposed face of the 

 unexpanded bulb. In Fig. 102 (/. st. a.), only the edge of this apophysis is 

 shown; but in Fig. 105. the broader face of it is represented. I designate this 

 {he lateral suhterminal apophysis as it occurs on the Literal aspect of the unexpanded 

 bulb, and also to distinguish it from an apophysis developed on the opposite 

 face of the bulb in a suhterminal position, which occurs in certain other genera, 



The terminal apophysis. — The embolic subdivision ends in a strongly chitinized 

 lobe, which may be designated the terminal apophysis 1 1 ig, 102. / a.). To apoph- 

 yses of this kind Menge applied the term retinacula; but as this term predicates 

 their function, which in some cases is obviously not that implied by the name, 

 I prefer apophysis with a modifying term indicating the position of the particular 

 apophysis described. 



113 



