154 DR. K. W. VERHOEFF ON BRACHYCHAETEUMA, 



there are sixteen bristles, viz., 4 + 4 in the middle part, 2 + 2 

 above the end on small papillae, 2 on the end itself and 2 close 

 under it. The bristles of the most anterior row are shorter 

 than the rest. There is no doubt therefore in regard to a 

 specific difference between palicolus Brol. and jurassicum 

 Verh. On the other hand a generic union of Macrosterno- 

 desmus and Titanosoma is still a matter for consideration. In 

 regard to this only a more detailed description of the position 

 of the defence glands in the former genus can make a decision 

 possible. 



The fact that I succeeded in detecting well-developed eggs 

 in several Titanosoma. with nineteen segments may be taken 

 as removing the last doubt as to these animals being really 

 sexually mature. The condition of these eggs is furthermore 

 of special interest. In the female from Kehlheim they are five 

 in number and thickly packed with yolk globules, round to 

 oval in shape, slightly separated from one another, arranged 

 in line one behind the other, and, so disposed, measuring 

 together half to two-thirds of the width of a segment. They 

 occur in the region of the twelfth to the sixteenth segments. 

 In two of the females from England I found only four similar 

 eggs in each, likewise in the region of the twelfth to sixteenth 

 segments. Here, however, they appeared two by two, pressed 

 together by their ends to such an extent as to produce flatten- 

 ing, and much more drawn out in shape, for the most part 

 one and a half to two times longer than broad. This linear 

 arrangement of a small number of eggs is in striking contrast 

 to what has been observed up to the present in other 

 Diplopods, most of which are capable of laying forty to two 

 hundred eggs. There is here further a noteworthy biological 

 parallelism with certain small land Isopods, especially with 

 many Trichoniscidas, which in similar contrast to their larger 

 relations carry only a few embryos in their brood-pouches. 

 In the case of Titanosoma there appears to be a still more 

 scanty progeny, and this circumstance, in conjunction with 

 the small powers of locomotion of such delicate and extremely 

 small representatives of the Polydesmoidea, is probably 



