§ 316. 
THE ARACHNOIDAE. 
891 
The lower Arazhnoidae produce only a small number of eggs at a time, 
but these are often of a size disproportionately large to that of the 
animal, 
As yet, only very incomplete researches have been made on the elements 
of the Sperm. 
considerably in the various groups. 
It appears, however, that the spermatic particles differ 
Those of the Tardigrada have the 
cercarian form; those of the Scorpionidae, on the contrary, are simply 
filamentoid. But both kinds have very active movements which are 
suspended by the contact of water. 
contains spherical or reniform motionless corpuscles.” 
The Sperm of the Araneae always 
With the Aca- 
rina, the spermatic particles are motionless and of most varied forms. 
by Wittich (Observ. quaed. de Aranearum ex ovo 
evolut. Dissert. Halis, 1845, fig. 1, A.).* 
4 With the Tardigrada, the eggs are very large, 
as are also those of Oribates, Sarcoptes »nd De- 
modex. 
5 See Doyere, loc. cit. p. 354, Pl. XVI. fig. 5 
(Macrobiotus), and Kélliker, Schweiz. Denkschr. 
VIIL. loc. cit. p. 25, Taf. II. fig. 16 (Scorpio euro- 
paeus). I have observed that the characteristic 
movements of the spermatic particles ceased in- 
stantly from contact with water, and that the par- 
ticles themselves became twisted and doubled. 
6 With Tegenaria, Salticus, Lycosa and The- 
ridion, the spermatic particles have the form of 
round cells, while those of Micryphantes and 
Clubiona are reniform or semilunar. They are 
formed in groups inthe mother-cells. With Tege- 
naria, a round nucleus is easily distinguished in the 
velopment, and that their definite form would be cer- 
carian. But I quickly abandoned this idea when I 
found the same form in the seminal receptarle of 
the females, where, evidently, the spermatic parti- 
cles cannot be present except in their perfect state. 
7 With Trombidium, Zetes, Oribates, and 
Hoplophora, the spermatic particles are developed, 
as I have satisfied-myself, under the from of very 
smal, rigid corpuscles, in very large cells. With 
Bde.i2, they are produced in a similar manner, but 
are fusiform. With other Acarina they are found 
of remarkable forms. Thus, in the testicles of the 
Hydrachnea and Gamasea, I have observed round 
masses of cuneiform bodies, at the larger extremity 
of which there was an oblong granular spot. I 
have also satisfied myself that these motionless 
spermatic particles of such large size are preceded 
in their dev by round leated cells. In 
spermatic particles. With Lycosa, this nucleus is 
oblong, curved and attached to the wall of the cell; 
and this led me at first to think these cells were 
the spermatic particles in their first stages of de- 
* [ § 316, note 3.) The development and struc- 
ture of the eggs of Araneae have recently been 
carefully studied by Wittich (Die Enstehung des 
Arachnideneies im Eierstocke, die ersten Vor- 
gange in demselben nach seinem Verlassen des Mut- 
terkérpers ; in Muller’s Arch. 1849, p. 113), and 
oy J. V. Carus (Ueber die Entwickelung des Spin- 
neseies, in Siebold and Kolliker’s Zeitsch. II. 
1850, p. 97). The structure of the ovary of these 
animals is no Jess beautiful than singular ; it re- 
sembles a bunch of grapes enclosed in a common 
capsule. The eggs are developed, each, on the ex- 
tremity of a pedicle which is attached to the main 
stem or rachis. The details of the development of 
the ova are briefly as follows: On the extrem- 
ity of the pedicle appears a delicate vesicle, or cell, 
which ins a leated cell. This 1 
cell is the germinative vesicle, with its dot, and 
does not increase so rapidly in size as the vesicle 
in which it is contained ; but this last dilates and 
expands, and minute cells appear in the liquid, 
lying between its membrane and the germinative 
vesicle. These newly-formed cells constitute the 
vitellus ; and when the ovum is completely formed, 
it consists of vitellus in which is concealed the 
germinative vesicle with its dot. Ina word, the 
ovum is here formed as elsewhere, except that it is 
developed on the extremity of a pedicle. In regard 
to the peculiar bodies mentioned above by Siebold, 
as found in the vitellus, their presence and struc- 
ted 
the testicles of Ixodes ricinus, I have seen count- 
less transparent staff-like ‘bodies, pretty long and 
large, motionless, but swollen at one of their ex- 
tremities when placed in water. 
ture have been observed by both Wittich and 
Carus; they are composed of concentric layers 
around a nucleus. Of their nature and function 
nothing is known. — Ep. 
+ [§ 816, note 7.] I have studied the develop- 
ment and nature of the spermatic particles of the 
Araneae and Acarina, but with results different 
from those above mentioned. With the first of 
these, they are developed, as usual, in special 
daughter-cells, and invariably consist of an arcuate 
staff, to which is attached a short but very, very 
delicate tail; indeed, this tail is so tenuous that 
only the best and highest microscopic powers can 
bring it out. It escaped the watchful eyes of Wag- 
ner and Leuckart, and led them to adopt errone- 
ous views of the formation of these bodies (see 
Art. Semen, Cyclop. Anat. & Phys. fig. 374). 
With the Acarina, the particles have the same 
form and character, but are much more minute and 
difficult of examination. It would appear from the 
description given above by Siebold, that he must 
have taken for spermatic particles the peculiar 
granule-like bodies found in the sperm of the 
Araneae. These bodies are very hydroscopic, but 
are homogeneous, and although I could make out 
nothing further as to their structure, yet it is evi- 
dent that they are wholly different from the true 
spermatic particles, and cannot be considered as 
either undeveloped or modified forms of these last. 
—Ep. 
