732 SUMMARY OF CURRENT RESEARCHES RELATING TO 



in doubt as to the function of an apiicndago of the male generative 

 apparatus which is nearly one-fourth of the size of the whole body of 

 the animal. 



In Cypris monacJia the organ is thus constituted : it is made up of 

 a chitinous framework, a contained glandular tube, and an investing 

 musculature. The framework consists of a chitinous tube f<jrmcd of 

 about sixty rings connected by a membrane, and of the S2)iucs placed 

 thereon. Every ring carries several s])ines, which, at the j)roximal and 

 distal ends, are arranged in circlets, and are specially attached at their 

 tips by a strong chitinous ring ; while all the rest stand at right angles 

 to the long axis these are inclined outwards, and so form funnel-like 

 structures, in the walls of which the spines run like ribs. These spines 

 consist of one piece, while all the rest not only divide into two arms, 

 but each of these breaks up again into two secondary arms, which are so 

 arranged that the last arm of one and the first of the following spine 

 always belong to the same ring. 



The chitinous tube passes at its hinder end into a knob-shaped 

 enlargement, which very rapidly narrows to a fine eficreut duct which is 

 proi)ortionately short, and opens into the penis ; at its anterior end it 

 passes into a shallow cup which is bored by a narrow orifice hardly 

 \vidcr than a spermatozoon ; around the inner concave side of this small 

 chitinous cup corpuscles are arranged. Thence a tube is invaginated 

 into the chitinous tube ; this appears to consist of a single layer of cells, 

 but the examination of young forms teaches that the layer is double. 

 This invaginated tube only extends to about the middle of the chitinous 

 tube; the rest of the latter contains a secretion which is coloured a 

 light-blue by hfematosylin, and which passes into the eftcrent duct, and, 

 when the latter is injured, escapes as a small, mucous, and highly re- 

 fractive droplet. The secretion is probably formed by the cells of the 

 invaginated tube, for which the author proposes the term of glandular 

 tube in place of Nordquist's name of internal epithelium ; this secretion 

 is of great importance for the spermatozoa, which, in Cypris jmndata, 

 were observed to be rolled up in it. 



After some observations on the difierences which obtain in different 

 species, the author proceeds to inquire how the apparatus works. The 

 activities of the muscles and of the spine-arms appear to be antagonistic, 

 for the rings of the chitinous tube are approximated by the contraction 

 of the muscles, while, when these relax, the elasticity of the spines must 

 tend to separate the rings from one another. In this way the chitinous 

 tube is alternately, and rapidly, shortened and elongated. We have, 

 therefore, to do with a pumping apparatus, the suction-power and driving 

 power of which are produced by the alternate action of the spine-arms 

 and muscles. The shallow cup at the anterior end of the tube seems to 

 act as a valve. As soon as the spermatozoon has completely entered the 

 apparatus it must be driven out into the ductus ejaculatorius by renewed 

 shortenings of the tube. 



It may be concluded that the " slime gland " is morphologically an 

 invagination of the vas deferens into itself; its function is to isolate the 

 spermatozoa which lie collected ia quantities in front of it, and to pump 

 them onward. It may also, as Weismanu has suggested, have some 

 cjaculatory power. 



