400 



SCIUJSfCB. 



[Vol. VIII., No. 195 



scribed for the first time. A few simple ascid- 

 ians, overlooked previously, find a place in an 

 appendix. 



Compound ascidians were figured by Ronde- 

 letius as early as 1555, but nothing of their struc- 

 ture was put on record until two hundred years 

 later. Even then their relation to the simple 

 ascidians was not suspected, though some of the 

 main points in the anatomy of the latter were 

 known to Aristotle. 



Gaertner in 1774, and Renier in 1793, recognized 

 the relations of one or two genera, but the ma- 

 jority of naturalists still confused the compound 

 ascidians with Alcyonaria or with sponges. It 

 was reserved for Cuvier and Savigny to demon- 

 strate beyond all question the close afiinity be- 

 tween the two groups of the Tunicata. This was 

 in 1816 ; and, led by these investigations, La- 

 marck, about the same time, instituted the class 

 Tunicata. Since then important researches on 

 the compound forms have been made by Milne- 

 Edwards. Gegenbauer, Krohn and Metchnikoflf, 

 Ganin, Giard, and von Drasche, as well as other 

 students ; while Professor Herdman, in the pres- 

 ent paper, has summarized the existing knowl- 

 edge, and added many remarkable anatomical 

 discoveries of importance for the history of the 

 group, to say nothing of the multitude of details 

 useful to the special student, and evincing a 

 thorough and patient method of study which 

 enforces confidence in and gratitude for his pro- 

 longed investigations. 



Dr. Theel, in the second part of his work on 

 the holothurians, has not limited his labors to a 

 description of the Apoda and Pedata which were 

 brought home by the Challenger, but has added a 

 short exposition of all the shallow-water forms 

 hitherto known. It was rightly considered that 

 such a monograph was highly desirable, though 

 the difficulty of its preparation was very great, 

 and various gaps necessarily occiu- in it on account 

 of the frequent impei'fections of the descriptions 

 given by some authors. Material from many 

 sources was put at the writer's disposal, especially 

 the very rich collection of the Royal zoological 

 museum at Stockholm. 



The examination of the vast harvest of the 

 Challenger voyage indicates a double derivation 

 for the deep-sea holothurians. The Elasipoda, 

 though species are found occasionally in shallow 

 water in the arctic regions, cannot be derived 

 from the same source as the usual shallow-water 

 types. On the other hand, a certain proportion 

 of the deep-sea species, such as forms of the 

 Cucumariae, show intimate relations with the lit- 

 toral fauna. The relations of the littoral to the 

 abyssal fauna are discussed in an admirable man- 



ner by Dr. Theel, who regai'ds the primitive 

 holothurian to have been shaped like Cucumaria, 

 with an open stone canal, feet, and a well-de- 

 veloped ambulacral system. Some forms have a 

 great range in depth, the same species varying over 

 seven hundred fathoms. Shallow-water genera 

 sometimes reach a depth of some twenty-nine 

 hundred fathoms, while the species are usually 

 different from those of more moderate depths. The 

 characteristic deep-sea forms, however, are the 

 curious Elasipoda, which, as above mentioned, 

 rarely are found except in the abysses. 



Not a single species is common to the Arctic 

 and Antarctic seas, though the shallow-water 

 fauna presents much the same characteristics, and 

 many of the species are very closely allied. Many 

 species are circumpolar, but only a few cir- 

 cumequatorial. About 45 forms are known from 

 the Arctic, 32 from the Antarctic, 135 from the 

 Atlantic and Mediterranean, but no less than 305 

 from the Indo-Pacific region, which, it would cer- 

 tainly seem, must be the metropolis of these forms 

 of animals. 



The great value of Dr. Theel's work is self- 

 evident, and only the limits of our space pre- 

 vent a more thorough analysis. As it is, we 

 have given but a few indications of the wealth it 

 contains, for which the reader must be referred to 

 the original. 



According to the latest returns published by 

 the minister of agriculture, it appears, says the 

 Journal of the Society of arts, that the chestnut - 

 tree is cultivate^ in every province of Italy, ex- 

 cepting those of Milan, Cremona, Mantua, Rovigo, 

 Ferrara, Ancona, Bari, Lecce, Syracuse, Girgenti, 

 and Trapani, that is to say, it is cultivated in 56 

 provinces ; and that, out of the 8,257 communes 

 in Italy, it is cultivated in 1,313. The chestnut 

 is cultivated on the most extensive scale in Liguria, 

 and on the least in Sardinia. The total produc- 

 tion throughout the kingdom, of fresh chestnuts, 

 is 391,393 tons annually, which would average 

 1.33 kilograms per inhabitant; in Liguria it reaches 

 101.5 per head, and in Sicily only 3.57. A consid- 

 erable quantity of chestnuts is exported to 

 France, Austria, Egypt, Switzerland, and South 

 America ; while, on the other hand, a very in- 

 significant quantity is imported from France, 



Austria, and Switzerland. 



« 



— A Parisian electiucian has devised a mode of 



utilizing the residual liquids from bichromate 



and other powerful batteries. He mixes a porous 



acid-proof substance with the residual liquids, 



dries the paste thus produced, and uses it as a 



charge for batteries for telegraphic purposes. 



