ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 445 



the nephridia become modified to form a genital duct, by a fusion of 

 a series of nephridia, by a disappearance of a part of the nephridium, 

 or by a shifting of the position of the pore. The large Microchseta 

 rappi {Lumhricus microclietus) is described in detail ; and the more 

 noticeable points are the small size of the prostomium and setse, 

 the large size of the nephridiopores, the very large size and compli- 

 cated structure of the nephridia, the excessively strong septa of the 

 anterior somites, the numerous small spermathecae, of which there is 

 more than one pair in a somite, the bifurcation of the dorsal trunk in 

 five of the anterior somites and the great enlargement of its wall in 

 somite VIII. 



Slavina and Ophidonais.* — Mr. E. C. Bousfield disputes 

 Vejdovsky's opinion that Nais appendiculata d'Udekem is identical 

 with N. lurida Timms, both of which belong to Vejdovsky's new 

 genus Slavina. The author has examined numerous specimens of the 

 latter species which he describes and figures ; he gives a figure from 

 Vejdovsky of S. appendiculata, and points out the differences between 

 the two species. After remarking on the differences in the arrange- 

 ment of the capillary setae, he points out that, whereas S. lurida has 

 only six or eight " touch-organs " in a ring round each somite, and 

 that they are absent on the ventral surface, in S. appendiculata, on the 

 other hand, as many as twenty of these occur in a ring, which passes 

 across the ventral surface. In the former the eyes are purple, in the 

 latter brownish- black. A description follows of Ophidonais serpentina 

 Gervais, which the author considers as belonging to Vejdovsky's genus 

 Slavina, as it has tbe characteristic " touch-organs " and in other 

 respects agrees with the other two forms. The capillary setee are 

 frequently absent in many of the anterior and posterior segments, and 

 even when present the number is reduced to one in a bundle ; the 

 " touch-organs " are irregularly placed, more or less in rings, and are 

 especially numerous on the head. In conclusion the characters of 

 these three species of Slavina are summarized. 



Musculature of Chaetopoda.t — Dr. E. Eohde reviews the more 

 important investigations of Chsetopod musculature, and reports the 

 results of his own widely based studies. In Branchiohdella, which 

 he discusses first as a good illustrative type, the longitudinal mus- 

 culature of the body consists of very large, partly ccelomyary, partly 

 completely closed muscle-cells, in which the contractile rind is clearly 

 separated from the nucleated medullary substance. He traces the 

 development of these muscle-cells from very granular, large cells 

 with central nucleus and distinct membrane, which differentiate into 

 fibrils on one side, and thus become platymyary. The fibrillar layer 

 becomes strongly developed, and bends round, forming the ccelomyary, 

 and lastly the completely inclosed tubular form. The muscle-fibres 

 of the Chaetopoda exactly resemble those of Branchiohdella, and each 

 is the equivalent of a cell, whose outer membrane forms the sarco- 

 lemma. The fibres are completely inclosed, but in Phreorydes and 



* Journ. Liun. Soc. Lond., xix. (1886) pp. 264-8 (1 pi.), 

 t Zool. Beitr. (Schneider), i. (1885) pp. 16i-205 (4 pis.). 



