ZOOLOGY. 425 



proved to be the larva was, however, with as little doubt, referred to the 

 Echiiioderms. lu its adult couditiou it has an internal branchiferous 

 <anal, which simulates that of the Tunicates. What, then, are its 

 affiuities ? 



As early as 1870 Metschuikoff considered that it might be really 

 related to the Echinoderms, as its larval condition suggested. This 

 view lias not found much favor, but during the past year he reiterated 

 it and fortitied it with new arguments, based chiefly on its development. 



Balanofjlossiis, then, resembles the Echinoderms in the longitudinal 

 baud of cilia, the water-vesicle opening by the dorsal pore, and the 

 peritoneal sacs, while the two hinder circlets of cilia and the terminal 

 anus are developed in some Echinoderms, and the latter is always 

 found in the youngest stages of all typical Echinoderm larvce. The 

 histological characteristics are equally repeated in the Echinoderms. 

 The course of development is also similar in the two. In short, Metsch- 

 nikoft" insists on retaining Balanoglossus with the Echinoderms in the 

 same branch or sub-kingdom — or ^'type," as he prefers to call it — and 

 gives to that type the comprehensive name, Ambulacraria. Balano- 

 glossus is isolated, as a "sub-type" named Bilateralia, and the typical 

 Echinoderms form another renamed Badiata. 



The observations of Metsclinikoff have been reviewed by Prof. A. 

 Giard, and supplemented by the French naturalist's own investigations. 

 He calls special attention to the existence, in the Tornaria state, of a 

 l)eculiar heart, which no Echinoderm is known to possess, the compara- 

 tively late development of the ciliated circlets, and the presence of a 

 muscular band connecting the dorsal aquiferous system with the median 

 point of the eye-spots — all presenting difficulties in associating; Balano- 

 (jlossus with the Echinoderms. ISTevertheless, Giard is disposed to coin- 

 cide with Metschuikoff in approximating the one to the other, whik; he 

 does not venture to pronounce on the i)hylogenetic relationships of the 

 two. He even suggests a new argument in favor of the approximation, 

 in the possibility of a similarity of the two in the development alike of 

 excretory and deutoplasmigenous functions, at certain times of the year, 

 of the genital glands. He unqualifiedly repudiates the idea that there 

 is, as has been claimed, any genetic relationship between Balanoglossns 

 and the Tunicates. (J. E. M. S., (2,) II, p. 194, from Bull. Sci. Dep. 

 Nord, IV, pp. 372-378.) 



WORMS. 



ORTHONECTIDS. 



Metschuikoff (El.). Observations on the Orthonectida. Abstr. in Jourii. R. Micro- 

 »cop.Soc. (2,) V. 1, pp. 461-4()'2. 



Characteristics and relations of the Orthonectids. 



In the notice of the progress of zoology in the Smithsonian Keport for 

 1880, reference was made to the newly proposed "class" of Orthonectids. 



