504 HYATT'S REVISION OF THE 



steamer of the United States Fish Commission, continued during several summers in Long 

 Island and Vineyard Sounds, and south of Cape Cod, there was found upon hard bottom 

 but one specimen of Suberites compacta Verr. This had formed a base of attachment, not 

 to the top, but fo the side of a stone, and did not rise in branches, as is usual with sponges 

 growing habitually on hard bottoms, but lay flat, as if upon its natural bed of sand. In 

 the same way, no change beyond what is necessary, takes place in the skeleton of Tethya^ 

 when it is found upon hard bottom, as is the case upon tlie English coast; a base of 

 attachment is formed, but the skeleton preserves its peculiar radiate arrangement, and 

 the typical shape is retained. How the law of " amixie " can be applied here, or to Mr. 

 Allen's observations quoted previously, I cannot see ; physical causes alone seem to be 

 sufficient to account for the variations, and the law of heredity, that like produces like, to 

 account for the persistence of a similar structure in forms, which, like the two last de- 

 scribed, have migrated from the habitat where they probably acquired their peculiar 

 oi'gauization. 



Ac-ain, accordina: to Weissmann's ideas, when a number of varieties enter a new and 

 isolated territory, those varieties can only produce a new form varying from the parent 

 species in the same way that they, as a whole, vary from the parent varieties as a whole. 

 Thus if the wanderers include many aberrant forms having a large majority of individ- 

 uals, the result of their crossing, when isolated together, would be a new aberrant form. 

 It would not be at all probable that these species would enter a new locality with precisely 

 the same, or even a similar assemblage of forms, and produce by " amixie " the same, or 

 a similar result ; but this is what must have been done in the present cases. 



These remarks and criticisms are applied strictly to the characteristics which have been 

 analyzed, and it is quite possible that when the anatomy, coloration, etc., come to be 

 studied, that results confirmatory of the conclusions of Weissmann may be obtained, but 

 the presumptions are now strong against this, especially in view of Mr. Allen's conclu- 

 sions, which deal with the same class of external characteristics so fully studied by Weiss- 

 mann among the insects. 



I mifdit also produce here, if it was essential to a clearer understanding of the subject, 

 instances among the fresh water Polyzoa which are no less responsive to physical influences 

 in certain important characteristics, but this is probably unnecessary. What I particularly 

 wish to point out, and in so fer, agree with Weissmann and several other evolutionists, is this, 

 that there are certain characters in every species, which, though presenting many variations 

 of a definite kind, do not arise through Natural Selection, and that naturalists who apply 

 that law without carefully studying, not only what may be due to physical causes but to 

 the tendencies and characteristics inherited from the ancestors of the group or species, are 

 not likely to attain results which will add so much to the knowledge of philosophical 

 zoology as if they had taken this side of the question into consideration. 



The following observations were made upon the larvoe of several specimens preserved in 

 alcohol, and though necessarily veiy imperfect, they are important, and seem to establish 

 the following propositions. 



1 Telliyn (/ravula, sp. n. Loc. Buzzard's B.ay, is a new spe- pebbles and sand sifted out of the mud, and, thus ballasted, 

 cies found growing on mud in shallow water, and sustained the animal is held upright under all circumstances. See 

 b)' a base of loose fibres, which like a net catch and hold also Johnson's Encyclopedia, article Sponges, by A. Hyatt. 



