210 Notes on the Embryology of Starfishes. 



XXIX. — Notes on the Embryology of Starfishes. 



(TORNARIA.) 

 By Alexander Agassiz. 



Read February 12, 1866. 



The Tornaria here described, PL II. Figs. 1-11, lias been 

 known to me several years. I did not include it in my former 

 papers on the Embryology of Ecliinoderms in hopes of ascer- 

 taining the Starfish of which it is the Platens ; as there is no 

 probability of determining this for the present, I have been 

 induced to publish these incomplete observations, since they 

 throw considerable light on the structure of a type of Echino- 

 derm larvae very imperfectly known. Miiller has given us 

 figures and descriptions of species of Tornaria found at Nice, 

 Marseilles, and Triest ;* the stages he has observed correspond 

 very closely to those I have found, which may be considered as 

 explanatory of his figures, and show more in detail how we can 

 recognise in them all the characteristic features of Starfish 

 Larvae. 



The resemblance of the oldest observed stages of Tornaria to 

 the younger stages of Brachiolaria (the Bipinnaria of Miiller) 

 is quite striking (compare Figs. 1, 2, with Fig. 11) ; and the pre- 

 sence of some features only fully developed in the adult Brachio- 

 laria (the brachiolar appendages), but existing in Tornaria in a 

 very rudimentary condition (Figs. 6-8), can leave but little 

 doubt that we are dealing with a Starfish Larva in spite of the 

 marked differences to be observed between them. Miiller had 

 already come to the same conclusion, and the arguments he 

 brought forward are only strengthened by the examination of 

 our species. 



There are such important points of difference between these 



* See Miiller's second, third, and fourth Memoirs on the Embryology of Echi- 

 noderms. 



