886 | Recent Literature. { December, 
by different authors been regarded as a vertebrate, a mollusk, as 
well as a crustacean, has been greatly needed. r. Oscar Hert- 
wig is so excellent a histologist and anatomist, that we may feel 
sure that this investigation has been made with the same exacti- 
tude which has characterizetl his previous labors on the lower 
animals. Our knowledge of Sagitta had already been greatly 
extended by the researches of Krohn and Kowalevsky, and owing 
n 
of Vermes is uncertain. Hertwig concludes that it agrees best 
with the Nematodes-and Annelides 
WapsworTH’s GEOLOGICAL iets i This papers by Prof. 
Walghoith are, like all the preceding ae of this author, of 
the most thorough character. He has made the microscopic 
study of sean and metamorphic rocks a ai study for sev- 
eral years, and by his thoroughness has elevated this department 
of geology very nearly to an exact science. The first paper, on 
the geology of Lake Superior, is the most important one, and 
contains six effective octavo plates, showing the relations of the 
different kinds of rocks to each other; the dykes, bands 8f iron 
ores, jasper veins, felsites, diorites are cleariy shown in their rela- 
tions to each other in the rock masses. Mr. Wadsworth has not 
relied on the microscope alone, but has given many important 
chemical analyses of minerals. The historical account of the 
explorations of others in that region, with the bibliography at the 
end of the memoirs, is very. valuable. We wish we could 
quote largely from these papers, but space will not permit.— 
PHYSICAL AND GEOLOGICAL RESULTS OF THE FRENCH ExPEDI- 
TION TO OBSERVE THE TRANSIT OF VENUS.2—These beautiful vol- 
umes are a portion of the results of the French Expedition to 
observe the Transit of Venus.’ The first part deals with the 
physical results of the expedition, printed in fine clear type with 
eighteen excellent plates, a portion of them photographic. The 
| Notes on the Geolozy ot the Iron and Copper Salhi of Lake Superior. By M. 
_E. Wadsworth. Bulletin of the Museum of Comparative Zodlogy at Harvard Col- 
lege, Whole Series, Vol. vit. (Geological Series, Vol. I). PP. He mn 6 plates. 
On th e Elongation and Plasticity of Pebbles in Conglomerate. . E. WADS 
WORTH. (From the Proceedings of the Boston Society of Rained History, Vol. xX, 
= Nov. 5, 1879.) 
_Danalite from the Tron Mine, Bartlett. New Hampshire. By M. E. WADSWORTH. 
- Picrolite from a Serpentine Quarry in Florida, Mass. By M. E. WADSWORTH. 
2 Mission de l Isle Saint-Paul Observations Astronomiques, aiaeag speak aph- 
igues, observations magnetiques et hydrographie. Institut = 2 ran e des 
Sciences. Recueil de memoires a l’observation du passage de said ae ya Soleil. 
(Extrait du tome 11, rst partie.) 425 pp-, 4to, 18 plates aad maps. 
Recherches iaa oa Eggi a Aden, a la Reunion, aux Isles Saint Paul et Am- 
ie , aux M. Cu. VELAIN, Maitré de conferences a la Sorbonne. 
cs te PP» Ato, site plate rje maps. (Extrait du tome 11, 2d partie.) Paris, 1879. 
