$ 294. THE CRUSTACEA. 361 
‘verse anastomoses. In front, the testicular vesicles are lost in these canals, 
which finally diverge from each other in an arcuate manner, as is also true: 
of the Vas deferens of the Glomerina. In this manner, these canals, as 
two Ductus ejaculatorii, extend to a triangular scale situated under the 
third thoracic segment, and terminate at the lower angles of this scale in 
‘two short, conical, penis-like protuberances, 
With the Chilopoda, the male organs are very complicated and formed 
upon a wholly different type. Their orifices are always situated at the 
posterior extremity of the abdomen. With some species, there is only a 
single, long, testicular tube into which pass two lateral, also very long, coe- 
cal tubes (Epididymes ?). At their point of junction, arise two short Vasa 
-deferentia, which terminate in a common, short, campanulate penis. Other 
Chilopoda have two to three varicose testicular tubes which anastomose, 
loop-like, at both of their extremities, and terminate, at last, in a longer or 
shorter Vas deferens, which bifurcates in its course, but its branches come 
together again in a short penis. With all the Chilopoda, the common geni- 
tal orifice is connected with the short excretory ducts of two to four oblong 
accessory glands, the nature of which is yet unknown.” 
§ 294. 
The Development of the Crustacea occurs, as with all Arthropoda, ac- 
cording to a special type.” 
After the disappearance of the germinative vesicle, a partial segmentation 
occurs upon a given point of the surface of the vitellus. 
transparent, finely-granular, proligerous disc is formed.” 
By this process, a 
The borders of 
this disc gradually extend over, and finally cover the surface of the vitel- 
lus. 
of the vitellus. 
It is then changed into a proligerous vesicle enclosing the remainder 
At the pole of the egg where the proligerous disc is first formed, are de- 
25 For the male organs of the Chilognatha, see 
Newport, Philos. Trans, 1842, loc. cit. p. 99; 
Rymer Jones, Cyclop. III. p. 551, fig. 314; and 
Stein, in Miller's Arch. 1842, p. 246, Taf. XII.- 
XIV. (Judus, Polydesmus, and Glomeris). The 
two testicles of Glomeris were formerly described 
as ovaries by Brandt; see his Beitr. loc. cit. p. 
325, Taf. XII. fig. 8 ; but he has rectified this in his 
Recueil, loc. cit. p. 157. For the copulatory 
organs of the Julidae, may be cited, also, the re- 
searches of Latreille, and Savi (loc. cit.). 
26 Lithobius has only a single testicular tube 
with two epididymes and four accessory glands 
(Treviranus, Verm. Schrift. II. p. 25, Taf. V. fig. 
7; L. Dufour, loc. cit. p. 87, Pl. V. fig. 2, 38, and 
Stein, loc. cit. p. 240, Taf. XII. fig. 1). Geophi- 
dus has three interanastomosing, varicose testicles, 
and two accessory glands (Stein, loc. cit. p. 243, 
Taf. XII. fig. 7). Judging from Muller’s figure 
loc. cit. Taf. IL. fig. 5), Scolopendra morsitans 
has also two ing varicose rt But 
this point is made somewhat uncertain from the 
researches of Kutorga (loc. cit. p. 10, Tab. IT. fig. 
4-6), who has shown positively the existence of four 
accessory glands with this animal. ZL. Dufour’s 
figures (loc. cit. p. 97, Pl. V. fig. 5) of the male 
organs of Scutigera indicate here a very different 
organization. There are two testicular tubes which 
unite loop-like at the anterior extremity and then 
send off a long very flexuous canal which has two 
pedunculated vesicles (Vesiculae seminales). The 
posterior extremity of these testicles is continuous 
into two Vasa deferentia which become dilated 
into as many Ductus ejaculatorii. Perhaps this 
abnormal organization of these animals in this re- 
spect, will be reduced from further researches to 
the type of the Scolopendra. 
1 The embryology of Crustacea has been brought 
out, especially by -the numerous and exact re- 
searches of Rathké ; see his Untersuch. tiber d. 
Biid. u. Entwickel. d. Flusskrebses, 1829, then his 
notes in Burdach’s Physiol. II. 1837, p. 250; his 
Abhandl. zur Bild. u. Entwickel. d. Mensch. u. d. 
Thiere, 1833 ; his Mittheilung. tiber d. Entwickel. 
d, Decapoden, in Muller’s Arch. 1836, p. 187, or 
in Wiegmann’s Arch. 1840, I. p. 241 ; and in the 
Neuest. Schrift. d. Danzig. naturf. Gesellsch. IIL 
Heft. IV. 1842, p. 23; then, Zur Morphol., Reise- 
bemerk. aus Taurien, 1837; his Beobacht. u. 
Betracht. tiber d. Entwickel. d. Mysis vulgaris, in 
Froriep’s neue Not. XXIV. 1842, p. 181; and 
finally his Comment. de Animal. Crust. generat. 
1844. See, also, Erd/, Entwickel. d, Huramereies, 
1848 ; and Joly, Sur le développ. des Caridina, in 
the Ann. d. Sc. Nat. XIX. loc. cit. p. 57, Pl. IV. 
2 Cancer maenas forms perhaps the only ex- 
ception in this respect. Here, the segmentation ap- 
pears to be complete ; see Rathké, m Froriep’s 
neue Not. loc. cit. p. 182; and Erdl, loc. cit. p. 
27. 
