clxxx GENERAL SUMMARY OF SCIENTIFIC AND 



mouth." Professor Allman adds " that the enormous depths 

 from which this colossal hydroid has been brought up should 

 favor the development of gigantic representatives of the di- 

 minutive forms of shallower zones, and that in the tenants 

 of these sunless regions of the sea we should find color not 

 less vivid than that of their light-loving relatives, are facts 

 full of significance." It is also to be noticed that the old 

 idea of pressure at great depths of the sea is entirely incor- 

 rect, as this animal is soft and jelly-like as in the Corymor- 

 pha of shoal water. No deep-water hydroid polyps, as 

 Allman remarks, produces medusae, not being able to endure, 

 " either before liberation from their parent hydroid, or for a 

 period however short in their free state, the darkness and 

 pressure and other conditions to which the dwellers in the 

 deep are exposed." 



More light has been thrown on the distribution and younger 

 stages of the gigantic polyps Umbellularia by Dr. Willemoes- 

 Suhm of the Challenger part3 r . In the Antarctic Sea it has 

 occurred as low down as 2600 fathoms. 



The growth of the common coral , Madrepor a cermcornis? 

 in the Florida Keys is estimated by Professor Joseph Le 

 Conte to be not more than three and a half to four inches 

 per annum. 



Little has been done in the Echinoderms, except by Pro- 

 fessor Carpenter, who from his examination of the nervous 

 and generative systems of Comatida, thinks that we should 

 be justified in removing the Crinoids much farther from the 

 rest of the Echinoderms than before. In fact, he thinks 

 they have little in common beyond the calcareous network 

 of the skeleton. To show how abundantly these crinoids 

 may occur, Dr. Carpenter states that he had learned from a 

 trustworthy observer that after a recent hurricane in the 

 West Indies a vast number of Pentacrini had strewed the 

 shore of Barbadoes, in all stages of growth, from one inch 

 to eighteen inches in length ; but unfortunately no natu- 

 ralist was at hand to reap the rich harvest. 



Further studies on the embryology of the Mollusca have 

 been made by M. Giard, Ussow, and Lankester. The two 

 latter have published their observations on the Cephalopods, 

 while the researches of Giard were made on Lamellaria per- 

 spicua, a gastropod. The development of Lamellaria requires 



