ZOOLOGY AND BOTANY, MICUOSCOPY, ETC. 965 



presence of sctas wliich traverse the carapace and are counectecl with the 

 body-wall. These sctaa completely corrcsi^ond to the seta3 of Annelids, and 

 they form a transverse row in the midst of each segment in some species. 

 Although, as a rule. Annelids are characterized by the presence of circular 

 muscles, yet such are absent from Poli/gordius. 



The external heteronoray of the segments in Echinoderes is almost as 

 well marked as in Annelids. The excretory organs of the two groups un- 

 doubtedly correspond, and, as their number varies among Annelids, we 

 need not wonder at their being reduced to a minimum in Echinoderes. The 

 absence of an orifice from the anterior end of the segmental organ of the 

 latter may be only apparent. 



On the other hand, we must not omit to notice the important differences 

 which undoubtedly exist between these two groups. These are the charac- 

 teristic union of the plates of the carapaces between the separate segments, 

 the absence of a distinct head, and the peculiarities of the musculature in 

 EcMnoderes ; this form wants the parapodia, cirri, and gills so characteristic 

 of Annelids, and cilia are found only in the excretory organs. Unless the 

 muscles which extend from the back to the ventral surface are dissepiments, 

 septa are wanting, and there is no ventral nerve-cord. No less important 

 differences are presented by the reproductive organs, the absence of a 

 circulatory system, the digestive organs, and the mode in which EcMnoderes 

 moves by the aid of its characteristic proboscis. 



All these are sufficient to prevent the union of EcMnoderes and Annelids 

 in a single class, and for the former it is proposed to establish a special class, 

 which, from the mode of locomotion, may be called the Kinorhyncha. The 

 characters which the two groups possess in common may be explained by 

 the supj)osition of the previous existence of a group of Proto-annelids (!), 

 whose body was segmented, and had sette and segmental organs of the 

 primitive form, terminating as do those of Cestoda and Trematoda. All the 

 suggestions here made must, however, be regarded as open to revision when 

 the development of EcMnoderes has been studied ; of this at present nothing 

 is known. 



The species of the genus appear to live at the bottom of the sea in muddy 

 and sandy places ; near shore, where shells of Mollusca abounded, it was 

 not found. In the neighbourhood of Odessa they do not live in any number 

 at less than seven or eight fathoms depth, but in the open sea they were 

 found in shallower waters. Eighteen species are already known, and the 

 genus is very probably cosmopolitan. 



Dinophilus gyrociliatus.* — Herr W. Eepiakhoff has made a fresh study 

 of the much discussed worm DinopMlus. («) In regard to the species, the 

 author maintains that the D. apatris so carefully described by Korschelt, 

 and other species described by various authors, are identical with the original 

 species discovered in 1848 by O. Schmidt, D. gyrociliatus. (h) His anato- 

 mical and embryological investigations corroborate those of Schmidt and 

 Korschelt, and the new points elucidated are relatively unimportant. The 

 author's attention was concentrated on the female form, (c) In regard to 

 the much discussed question of the systematic position of DinopMlus, 

 Eepiakhoff canvasses the various opinions, and especially those represented 

 by Lang and Korschelt, who refer it respectively to the Proto-annelids and 

 to the Tubellarians. He sums up by defining its position as that of a " side 

 branch from the Annelid stem, extricating itself from the Trochozoon type, 

 and developing between the Eotatoria and the Proto-annelida." 



* Mem. Soc. Ne'o-Rusa. Nut. Odessa, x. (1886) p. 2. Cf. Arch. Shiv. dc Biol., iv. (1887) 

 pp. 112-3. 



