INDUSTRIAL PROGRESS DURING THE YEAR 1874. C xli 



atively dry positions, and may be revived on supplying tliem 

 with more moisture ; but when the animals are actually dried, 

 they are incapable of being revivified. " Moisture," he adds, 

 " adheres tenaciously to earth, and Rotifers may rest in the 

 earth, like the Lepidosiren, until returning waters restore 

 them to activity." 



Dr. Salensky, of Kasan, Russia, has a paper, with several 

 plates, entitled " The Development of the Rotifer, Brachio- 

 nus urceolaris" in Siebold & Kolliker's Zeitschrift. 



An elaborate paper on the development of certain English 

 silicious sponges, by Mr. Carter, appears in the Annals and 

 Magazine of Natural History. It seems that the embryos 

 are cast off in July and August, as we have found to be the 

 case in similar sponges at Penikese during the past summer. 

 Many fine forms have been obtained by the United States 

 Fish Commission at Noank and in the Gulf of Maine. Laroe 

 collections have been made in Florida by Dr. Palmer, and, 

 with those dredged by Count Pourtales, we have in Ameri- 

 can museums tolerable material for a work on our native 

 forms. A remarkable sponge from the Gulf of Maine has 

 been described by Professor Verrill under the name of Dor- 

 villia echinata. It is four inches in diameter, and supported 

 on a broad, stout, but short peduncle, forming one half of the 

 total height. Other species discovered at great depths in 

 the North Atlantic by the British exploring expeditions have 

 been found in seventy to one hundred fathoms off the coast 

 of Maine. Mr. Carter has also published descriptions of 

 deep-sea sponges dredged by the English Porcupine expedi- 

 tion. Mr. Bowerbank's volume on Sponges has been pub- 

 lished by the Ray Society. 



The Radiates still receive attention from Mr. Alexander 

 Agassiz, who has completed his monograph of the Echini. 

 It occupies between seven and eight hundred pages, with 

 about fifty plates, and will long continue to form the stand- 

 ard work on the order. 



Count Pourtales has described some remarkable Crinoids 

 dredged by the late Professor Agassiz on the "Hassler." 



The development of certain jelly-fishes {Ctenophorai),\>Q,- 

 longing to the genera Idyia and Plersobrachia, has been 

 elaborated with great care and beauty of illustration by Mr. 

 A. Agassiz. He gives a connected account of their history, 



