ZOOLOGY AND BOTANY, MICROSCOPY, ETC. o69 



are organs which phiy the part of the Malpighiau corpuscles and the 

 tubuli contorti of Vertebrate kidneys. 



Among the Vermes, Chaatopods, Gephyreans, and Leeches were alone 

 examined ; small examples of Nereis cuUrifera were found to be very 

 suitable objects for examination, and fuller information than is here 

 afforded us is promised shortly. Carmine is got rid of by the nephridium 

 of the earthworm, but it is only a small part of the organ that is engaged 

 in so doing; the chloragogue cells also take up indigo-carmine. In the 

 Hiriidinea the relations are very complicated, and are not as yet com- 

 pletely understood. 



In the Echinoderniata, Tiedemann's bodies appear to be the excretory 

 organs of the water-vascular system, while the so-called heart or ovoid 

 gland is the excretory organ of the body-cavity ; both of these organs 

 appear to have the same reaction as the segmental organs of most 

 Annelids, that is, they excrete carmine and have a slight acid reaction. 

 Prof. Kowalevsky observed distinct contractions of the ovoid glands in 

 Echinoids ; though these were not regular pulsations, yet there were 

 repeated contractions of the whole organ. 



The arrangements of some Ascidians are very remarkable, for in 

 Phallusia mentula all the organs are imbedded in a stroma which 

 consists of a number of vesicles in which lie rounded concretions. If 

 indigo-carmine be injected into Ascidia mentula, crystals are found in 

 the secreting vesicles around the concretions already there, just as in the 

 case of the organ of Bojanus in Molluscs. The author concludes that 

 the Ascidians have organs which correspond to the renal canaliculi of 

 the Vertebrate kidney. 



In an additional note,* in which some further information is given, 

 the most interesting point is, perhaps, the discovery that if a dog con- 

 taining Echinococcus vesicles be fed for three weeks with carmine and 

 ammonia, the water-vascular system, and especially the larger lateral 

 trunks of Taenia echinococcus, become coloured red. 



MoUusca. 



Anatomy of Deep-sea Mollusca.f — Prof. P. Pelseneer, who had to 

 make a somewhat hasty examination of the deep-sea Mollusca collected 

 by H.M.S. ' Challenger,' arrives at three general conclusions : — 



(1) An organ of special sense, the organ of vision, may atrophy and 

 disappear in consequence of the absence of suflficieut light in the great 

 depths. 



(2) Correlatively, the organs of general sense may multiply and 

 acquire a high degree of development, as the labial palps of Trochus 

 infundihulum, and the siphonal tentacles of varied structure found in the 

 deep-sea Anatinacea and in Malletia. 



(3) The respiratory activity may diminish, and the gills become 

 rudimentary in various ways or may retain great simplicity of structure. 



a. Cephalopoda. 



Structure of Silurian Cephalopods.| — Dr. H. Dewitz calls attention 

 to the fact that in 1878 he demonstrated that the horizontal walls found 

 inside the air-chambers of Silurian Cephalopoda were of organic origin, 



* Biol. Centralbl., ix. (1889) p. 127. 



t Reports of the voyage of H.M.S. ' Challenger,' Zoology, xxvii., part Ixxiv. 

 (1888) 42 pp. (4 pis.). X Zool. Anzeig., xii. (1889) pp. 147-.')2. 



