ZOOLOaY AND BOTANY, MIOEOSCOPY, ETC. 657 



A few free-cells (corpuscles) are to be found in tlie blood. The 

 paper concludes with some comparisons between sexual and asexual 

 forms, and the descriptions of the two new species JV. liamata and 

 N.lurida. Many of the author's observations will be found to con- 

 firm the accounts of those who have preceded him. 



Glands of Morren in the Earthworm.* — C. Eobinet finds that if 

 the secretion from the glands of Morren is allowed to dry, experi- 

 ments prove that we have in it a mineral body ; further observation 

 shows that this is formed of carbonate of calcium, and its function 

 would appear to be : — 



1. To neutralize the acids of the humus, and to convert an acid 

 nutrient medium into a neutral one, a condition which is indispensable 

 for the digestion of the quaternary substances of the humus by the 

 digestive fluid of the hepatic glands. 



2. To transform part of the carbonate into soluble bicarbonate. 



3. The soluble bicarbonate acts on the humus, and forms soluble 

 salts from the insoluble acids of the humus. The ulmate of calcium 

 which is formed by the action of the ulmic acid on the carbonate of 

 calcium becomes soluble in the presence of an excess of carbonic acid. 



4. The soluble ulmate thus obtained is more easily absorbed in 

 the intestine. 



Processes of Division and Regeneration in Earthworms. f— 

 G. Biilow has directed his studies especially to Lumhriculus variegatus, 

 and he finds that, in addition to the usual sexual method, reproduction 

 may be effected by simple transverse division, when either the head 

 or the tail, or both, may be redeveloped. No zone of gemmation is 

 first formed, as in Nais, nor is the process of reproduction from behind 

 forwards, as Bonnet thought, but in the opposite direction. The 

 result of the process quickly acquires individuality, two days being 

 sufficient for the appearance of all the essential characters. Amon^ 

 other experiments, he relates one in which a worm was cut into four- 

 teen pieces, and of these thirteen became complete individuals • in 

 some cases the effects of the experiment were hardly satisfactory, 

 inasmuch as a worm that had been operated upon gave rise to two 

 equal caudal ends. The author's observations gain in value from the 

 exact and careful manner in which his results have been registered. 



Excretory Organs of Hirudinea.J— 0. Schultze has examined the 

 excretory apparatus of Clepsine complanata, G. hioculata, Nephelis vul- 

 garis, Aulostomum gulo, and Hirudo medicinalis. He finds that there 

 is a continuous connection between the narrowest and the widest 

 lumen of the ducts, and that as the lumina become wider the ducts 

 become less elaborately branched and the cells diminish in number ; 

 a gradation in the ramification and coiling of the lumina may be seen, 

 as we pass from Clepsine and Neplielis to Aulostomum and Hirudo. 

 The study of the development of the segmental canals gives indications 

 of a marked agreement in the typical structure of the excretory organ, 



* Comptes Eendus, xcvii. (1883) pp. 192-4. 



t Arch. f. Naturg., xlix. (1883) pp. 1-96. 



X Arch. f. Mikr. Anat., xxii. (1883) pp. 78-92 (1 pi.). 



