PROGKESS OP MICROSCOPICAL SCIENCE. 245 



Gastrula I consider as the truest and most significant embryonal form 

 of the animal kingdom." It leads in his view to the sponges, to the 

 Acalephfc, to the worms, to the echinoderms, to the mollusks, and to 

 the vertebrates, through Amphioxus. Embryonal forms which may 

 easily be traced from Gastrula, occur among the Arthropods (Crustacea 

 as well as Insects). In all these representatives of different stocks of 

 animals, the Gastrula always maintains the same structiu'e. From 

 this identity in form of the Gastrula with the representatives of the 

 different animal stocks (or sub-kingdoms), from the sponges up to the 

 vertebrates, he imagines an unknown stem-form of animals, typified 

 by Gastrula, which he calls Gastrcea. 



Recent Deep-sea DreJgings hy the ' Challenger.'— The following 

 extremely interesting letter which was sent from Professor Wyville 

 Thomson to Admiral Richards, has been j)ublished by the latter in a 

 late number of the ' Proceedings of the Royal Society.' The Professor 

 says: — " I have the j)leasure of informing you that, during our voyage 

 from the Cape of Good Hope to Australia, all the necessary observa- 

 tions in matters bearing upon my department have been made most 

 successfully at nineteen principal stations, suitably distributed over 

 the track, and including Marion Island, the neighbourhood of the 

 Crozets, Kerguelen Island, and the Heard group. 



" After leaving the Cape several dredgings were taken a little to 

 the southward, at depths from 100 to 150 fathoms. Animal life was 

 very abundant ; and the result was remarkable in this respect, that 

 the general character of the fauna was very similar to that of the 

 North Atlantic, many of the species even being identical with those on 

 the coasts of Great Britain and Norway. The first day's dredging was 

 in 1900 fathoms, 125 miles to the south-westward of Cape Agulhas; 

 it was not very successful. 



" Marion Island was visited for a few hoiu's, and a considerable 

 collection of plants, including nine flowering species, was made by 

 Mr. Moseley. These, along with collections from Kerguelen Island 

 and from Yong Island, of the Heard group, are sent home with 

 Mr, Moseley 's notes, for Dr. Hooker's information. 



" A shallow-water dredging near Marion Island gave a large 

 number of species, again representing many of the northern tyj)es, but 

 with a mixture of southern forms, such as many of the characteristic 

 southern Bryozoa and the curious genus Serolis among Crustaceans. 

 Off Prince Edward's Island the dredge brought up many large and 

 striking specimens of one or two species of Alcyonarian zoophytes, 

 allied to Mopsea and Isis. 



" The trawl was put down in 1375 fathoms on the 29th December, 

 and in 1600 fathoms on the 30th, between Prince Edward's Island 

 and the Crozets. The number of species taken in these two hauls was 

 very large ; many of them belonged to especially interesting genera, 

 and many were new to science. I may mention that there occurred, 

 with others, the well-known genera Enplectella, Hi/alonema, Umbellu- 

 laria, and Flabellum ; two entii-ely new genera of stalked Crinoids 

 belonging to the Apiocrinidee ; Pourtalesia ; several Spatangoids new 



