648 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Observations on Swiss Oligochseta.* — K. Bretcher communicates 

 some notes on the freezing of Eeulea ventriculosa and on the desiccation 

 of Psammoryctes plicatus and Lumbriculus variegatus. He also gives an 

 account of the distribution of Enchytraeids and otber families, and dis- 

 cusses the systematic characters of Enchytraeid species. 



Chloragogen of Oligochaeta.f — D. Rosa concludes that the typical 

 chloragogen is a modified peritoneum. Its elements are not derived from 

 leucocytes and do not give rise to them. The bases of the chloragocytes 

 always adhere to the matrix of the inner cuticula of the walls of the 

 blood-vessels. In the main the chloragogen is an excretory tissue, but it 

 may also serve as a deposition-area for reserve materials; and this second 

 function is the dominant one in Enchytrasidae. The reserves consist 

 essentially of fat-globules ; the excretions, usually yellowish, consist of 

 semi-fluid elastic spherules (chloragosomes) formed within the chlora- 

 gocytes from the blood. The occurrence of chloragosomes in the body- 

 cavity is due to the more or less accidental liberation or bursting of the 

 chloragocytes, and is not necessarily bound up with the function of the 

 chloragogen. 



Function of Chloragogen Cells.}— C. Bartolotti gives a preliminary 

 account of observations which he has made, independently of those by 

 Rosa, on the function of the chloragogen cells in Lumbricus and Allo- 

 lobophora. Their function is predominantly excretory, but they also 

 accumulate reserve materials. He believes that the excretory granules 

 consist in great part, if not exclusively, of uric acid, while the reserve 

 materials seemed to be glycogen. 



Spermatozoa of Allolobophora fcetida.§ — Katharine Foot and Ella 

 Church Strobell have demonstrated in these three centrosome-like struc- 

 tures — one at the base of the spine, one at the anterior, and one at the 

 posterior end of the middle-piece. They discuss the complications 

 which their discovery discloses, and direct attention to the following 

 facts — among others — (1) the complete disappearance of both male and 

 egg attraction-spheres at a definite stage of the egg's development ; 

 (2) the lack of decisive evidence that the rays of the male aster focus 

 at any one point in the middle-piece, or that the rays of the cone focus 

 at the base of the spine ; (3) an inconstancy in both size and form of the 

 egg centrosome at a given stage of the development of the spindle, and 

 a lack of evidence of any division of either egg or sperm aster. They 

 conclude that the centrosomes of Allolobophora present conflicting evi- 

 dence that demands rigid cross-examination. 



Development of Clepsine.|| — 0. Burger finds that Clepsine shows in 

 its development, as in its structure, a closer resemblance to typical 

 Annelids than is exhibited by Nephelis, Eirudo, or Aulastomum. 



The lateral cavities of Clepsine correspond to the primitive segmental 

 cavities of Ohastopods, for they originate in the same way. Burger 

 observed their dnisal as well as their ventral coalescence; they form a 

 dorsal cavity corresponding in origin to the ventral cavity. In Eirudo 



* Rev. Suisse Zool., x. (1902) pp. 1-29. 



t Mem. Accad. Torino, lii. (1902) pp. 117-44 (1 pi.). 



+ Reud. Accad. Lincei Roma, xi. (1902) pp. 449-51. 



§ Anier. Journ. Anat., i. (1902) pp. 321-7 (1 pi.). 



|| Zeitschr. wiss. Zool., lxxii. (1902) pp. 525-44 (3 pis.). 



