1871.] 355 [Morse. 



ment of such eggs is direct, without passing through a tadpole- 

 shaped larval state," with the following note, "with the alcoholic 

 specimens it is not possible to trace completely the early stages of 

 this development, or to be perfectly certain that these egg-like bodies 

 are genuine eggs, although some of them appear to contain at first, a 

 germinal vescicle." 



Further investigation will probably show that eggs passing through 

 such an anomalous development are different in their nature, and it is 

 not improbable that the simple Ascidian Eugyra and the compound 

 Ascidian Lissoclinum will also present a kind of egg which passes 

 through that course of development supposed to be typical of the 

 class. Prof. Yerrill, with his usual caution, expresses a doubt 

 whether the egg-like bodies he observed, were genuine eggs, in the 

 note just quoted. 



EXPLANATION OF PLATE I. 



The embryos from which these were drawn were about eight one-hundredths 

 of an inch in length. 



Fig. 1. Showing body of embryo and anterior end of axial, cartilaginous rod. 



Fig. 2. Two embryos showing fin rays at the junction of the tail with the 

 body. 



Figs. 3, 4. Showing caudal fin. 



Fig. 5. Tail of preserved specimen showing contraction of axial rod, leaving 

 cavity. 



Fig. 6. Entire drawing from preserved specimen, showing breaking up of 

 axial rod with fin rays. 



Prof. Agassiz said that he studied the embryology of the 

 Ascidians nearly twenty-five years ago, but that the appear- 

 ances described by Prof. Morse were new to him and of great 

 interest. He failed, however, to see more than a certain 

 analogy between the embryo Ascidian and Vertebrate. He 

 thought that if the Vertebrates had descended from the As- 

 cidians there ought to be some traces of the process in the 

 geological record but there was no evidence of this. 



Dr. Chas. Pickering remarked that the position of Amphi- 

 oxus among the vertebrates seemed doubtful to him. 



Mr. F. W. Putnam said he thought there was no rea- 

 son for regarding Amphioxus as an adult vertebrate. We 





