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immediate function. None of the cells of the blastoderm at 

 the stage ^hen the ova were cut could have had a function 

 in the immediately subseqvient development distinct from that 

 of its fellows. The cessation of development after a point was 

 due to the diminution of the ' matter of life.' Professor Hacckel 

 shows that the formation of the colony of Avhich these compo- 

 site Siphonophora are made up, takes place by budding from 

 the stomach of the original polyp developed from the e^g. An 

 interesting observation which he copiously illustrates is the re- 

 markably potent effect of disturbances, such as light, jarring of 

 the vessel in which the eggs are kept, &c., in modifying the 

 course of development of the larva and producing deformities. 

 It is just one of those pieces of evidence which Mr. Herbert 

 SjDencer will be glad of to help him in establishing his view 

 that the direct action of external agencies on the organism 

 (direct equilibration) as well as the indirect — natural selec- 

 tion — is efficient in producing species. Here we have a case 

 in which the slightest abnormality of condition produces, not 

 arrest of development, not death (phenomena which some- 

 time occur thus), but strange, seemingly irrelevant deformity; 

 hypertrophy of one part and atrophy of another, of a most 

 curious kind. 



The difference between the nematoj)hors of the larvae and 

 of the adult Siphonophors is another excellent point which 

 Haeckel makes. He points out very carefully and figures 

 the structure of the two, the larval being so much simpler as 

 to belong to another type. This interesting fact may well be 

 grouped with other cases of the presence in larvae of the 

 same organs as are present in the adult, but of another type, 

 e.g., the external gills of young ganoids and sharks, compared 

 with the gills of the adults, the bivalve shell of the larval 

 Anodon, and the shell of the adult, the six hooks of young 

 Taenia and the circlet of the hydatid ; most nearly parallel of 

 all, the very strange bristles of many larval Annelids, and the 

 totally different bristles of their advdt forms. 



The new genus CrystaUocles is remarkable for its dense 

 and firm character, contrasting so strongly with the other 

 Siphonophora. It has a series of hard masses or joints of 

 curious angular form which fit together supjjorting the 

 polypites. On account of these bodies Haeckel terms it 

 Crystal/odes. 



