198 M. A. Stecker on the Development 



thoroughly the freshly deposited eggs attached to the ventral 

 surface. These were placed in an inodorous oil, where they 

 continued their development for a time ; so that I was enabled 

 to attain a satisfactory notion of the rapid process of develop- 

 ment (the so-called segmentation) of the O'^g, and of the first 

 formation of the blastoderm. Theeggs and embryos hardened in 

 absolute alcohol also furnished very good objects of observation. 



In this preliminary communication I will only call the 

 reader's attention to the most interesting points, without 

 entering into details, reserving the detailed description of 

 the entire process of development, with figures of the particular 

 formative phases, for a later publication. 



In general we must distinguish three principal phases in 

 the development of Chthonius. The first of these embraces 

 those egg-formations which take place in the body of the 

 mother ; the second includes the metamorphosis of the fresh- 

 laid eggs up to the complete development of the blastoderm — 

 that is, to the first change of skin ; and the third and last 

 phase is presented by those changes which occur in the newly 

 hatched larvae (analogous to the NaupUus stage) on the ven- 

 tral surface of the mother. 



In this preliminary communication we shall take into con- 

 sideration only the first and second phases, as these have not 

 been described by Metschnikoff with the same accuracy as 

 the third phase, the larval stage of Chelifer *. 



The ovary forms an unpaired gland, which has already 

 been correctly described and figured in the Chernetid^ by 

 Menge f 5 the individual ova,, which become larger and more 

 and more fitted for deposition the nearer they are to the paired 

 oviduct, give to the ovarian gland a racemose form. As has 

 already been correctly remarked by Menge \, the female geni- 

 tal organs open by two orifices at the second abdominal seg- 

 ment; the apertures are placed very near together. A depression 

 situated in front of them serves to provide the deposited eggs 

 with a sticky mass, secreted by a gland which opens here. 



The youngest ovicells are found imbedded in the interior 

 of the ovary. During the further development of the ovicell 

 (consistingof protoplasm, Purkinje'svesicle, and germinal spot), 

 which takes place in the same way that has already been 

 described by Metschnikoff in the eggs of the scorpion §, tliB wall 



• MetschnikoflF, /. c. pp. 518-522. 



t A. Menge, '' Ueber die Scheerenspinnen, Chernetidse,'' Neueste 

 Schriften der naturf. Gesellsch, zu Danzig, v. (1855), 2, p. 17, pi. 2. fig, 10. 



X Menge, /. c. p. 17. 



§ Metschnikoff", "Embrvologie des Scorpions," Zeitschrift fiir wiss. Zool. 

 Bd. xxi. (1871), pp. 204-232, pis. xiv.-xvii. 



