288 NATURAL SCIENCE. November, 



without their eflfect upon the evolution of the race, since through 

 them environment may act upon variation indirectly. In a word, he 

 supposes that an existing modification opens a way for the occurrence 

 of a similar variation. The modification is, ex hypothesi, in accord 

 with the environment, and its existence in the parent permits of 

 variation in a similar direction in the offspring. He illustrated this 

 by comparing the tendency to variation to the swinging of a number 

 of pendulums in all directions, while the action of the environment or 

 the action of the existing structure of the parent acts as a check on 

 the pendulum swing in a certain direction, though permitting it in 

 those directions that are harmonious with the existing structure. 

 Thus any further modification of parental structure opens a new 

 plane for the swing of a new pendulum. 



Unfortunately the subsequent speakers did not, for the most 

 part, direct their remarks toward this thesis of Mr, Lloyd Morgan's. 

 We shall therefore confine ourselves to urging the following difficulty. 

 The modification induced by environment arises necessarily after the 

 fertilisation of the ovum, and in most cases a considerable time after 

 that event ; variation, on the other hand, either is inherent in the 

 ovum or spermatozoon, or is a result of the process of fertilisation. 

 In the life of a single individual it is obvious that no modification can 

 affect variation, since this is necessarily antecedent. Again, to 

 suppose that a modification of either the male or the female parent 

 affects potential variation in the spermatozoon or the ovum, is merely 

 to re-state, in other words, that a change of environment which affects 

 the parent likewise affects the generative products ; and such a 

 statement is nothing more or less than Cope's theory of Diplogenesis, 

 which already holds the field as one of the main theories of the 

 Neo-Lamarckian. 



Are we Descended from King-crabs ? 



The next important discussion in which the zoologists took part 

 was that which, by an innovation in the Association's procedure, was 

 permitted to follow the Address of the President of the Physiological 

 Section. Dr. Gaskell took this opportunity of forcing on the atten- 

 tion of biologists the theory which he has previously put forward 

 more than once, that the Vertebrata are descended from Arthropoda, 

 the points of connection being represented among recent animals by 

 Aminoccstes, the larva of the lamprey, on the one side, and hy Limulus, 

 the king-crab, on the other. It is certain that during the two hours 

 in which Dr. Gaskell delivered his very remarkable address he was 

 able to adduce a quite astonishing number of coincidences in struc- 

 ture, as shown in the annexed table ; and it is a striking fact that his 

 hypothesis should have led him to the discovery of structures pre- 

 viously unsuspected, such as the sense-organs in the flabellum of 

 Limulus and the camerostome of Thelyphonus, which he claims as 

 corresponding to the auditory and olfactory organs of Avinwccetes. 



