390 History of the Hairy -backed Animalcules. 



Dr. Max Schulze, describing yet another genus, Turbanella 

 (Pl. ii. Fig. 15), in 1853,* took occasion to institute an elaborate 

 examination of the structure of the whole group, augmented by 

 all these discoveries. He considers that it does without doubt 

 fall within the great circle of Vermes, though there is some 

 difficulty in determining in which class to place it. Its union 

 with the Rotifera he judges impossible : 1, because of the ab- 

 sence of the vibratory organs around the mouth, so characteinstic 

 of that class ; 2, because muscles, nerves, and water-vessels — 

 organs which are wanting in no true Rotifera — have not been 

 found in this group ; 3, because of the absence of a caudal ex- 

 tremity, furnished with articulated members ; and 4, because of 

 the peculiar cilia with which the ventral surface is clothed in 

 the Chastonotes. Turbanella shows traces of a division into 

 segments in the separation of the head from the rest T)f the 

 body, in the ring of cilia which surrounds the head, and in the 

 position of the almost regularly recurring lateral processes, and 

 thus reminds us, in its ciliation and its obscure articulation, of 

 several states of development of the true Annelida. I may add, 

 that the Echinodera of Dujardin, and my own curious genus, 

 Taphrocampa (Figs. 17 — 19), presently to be described, carry 

 this appearance of segmentation still further, and, fro tanto, 

 strengthen the grounds of affinity with the Annelida. 



Dr. Sclmlze cites the analogy of certain Annelida, which 

 possess, even in the adult condition, a ciliated skin. Polyoph- 

 thabn/us (Quatref.) has a ciliary head- veil, not unlike that of the 

 Rotifera. The genus Spio is provided, according to Oersted 

 (confirmed by Schulze' s own observations), with ciliated gill- 

 leaves ; its two long frontal cirri are also ciliated, and so are the 

 puir of longer appendages, which, seated on the second seg- 

 ment, project at right angles from the body, as noticed in a 

 species found at Cuxhaven. 



The claim of the Tuebellaria to afford a refuge for these 

 strangers j which, like homeless paupers passed from parish to 

 parish, are found so difficult to settle, is next brought under 

 review. All bhe Vortex-worms have a ciliated covering, spread 

 entirely and uniformly over the body ; their skin is soft and 

 melting; their digestive canal is destitute of a firm envelope, 

 and is separated from the soft parenchyme of the body only by 

 its w;ill, formed of peculiar digestive cells, or hepatic cells. 

 Muscle-threads, the central portion of a nervous system, and 

 water-vessels, arc recognized in all these worms. f In Chce- 



* Arch/bo f. Anal. Pfytigl, eto, 1H.">:{, p. 211, etseq. 



t " In Miorottomum lineare, in which neither Oskar Schmidt nor I could for- 

 merly diaoorerany traoe of a water- vascular system, I have lately recognized such, 

 furnished with very small tremulous tags, and also distinct muscle-threads." — 

 Note by Dr. Schulze. 



