290 Dr. V. Sterki on a new Infusorian. 



armed with a, regular comb of long teeth projecting from the 

 inner margin of the lower face. Sixth segment of the abdo- 

 men of the female with a smooth enclosure on the disk. The 

 seventh segment in the male with a triangular pyramidal 

 projection on the disk, the apex of the projection obtuse, the 

 anterior and longest side polished. 



XXXII. — Tintinnus semiciliatus, a new Species of Infusoria. 

 By Dr. V. Sterki*. 



There are so many " new species " of Infusoria that it is 

 hardly fair to publish separately the discovery of a single one. 

 As regards the present species this course is taken because it 

 appears specially adapted to interest us, with regard to the 

 establishment of certain morphological characters. 



The body of the animal is of the same form as that of Tin- 

 tinnus JZuviatilis, St., — elongated, usually drawn out at the 

 hinder end into a peduncle, by which it is fixed in a tube 

 formed and inhabited by it. This peduncle is thin, but not 

 abruptly marked, the body passing gradually into it. The 

 mode of contraction is characteristic, and differs both from 

 that of the Vorticellina3 and of the Stentorinaj ; the peduncle 

 simply shortens until it almost disappears, but without the 

 body essentially changing its form. The animals were fre- 

 quently to be met with outside the above-mentioned tubes. 

 Whether they had fallen out, or, in other words, had been torn 

 out, or whether they occur so normally, I am unable to say. 

 The latter is the more probable supposition from the analogy 

 of T. fluviatilis ; only it may be remarked that even after the 

 lapse of considerable time they had not commenced the forma- 

 tion of new tubes. In this "free" state they were entirely 

 destitute of a peduncle, an indication of which was frequently 

 to be seen only as a little stump ; otherwise the body was 

 perfectly rounded behind. In some cases a portion was half- 

 constricted off behind ; this state was probably produced 

 traumatically by pressure. Even when observed for a long 

 time this constriction went no further ; so that in this case 

 there could be no question of division. The length of the 

 body (without cilia) is 0-04-0-06, with the peduncle 0-1-0-12, 

 and the diameter about 0*03 millim. 



At the anterior end the body is somewhat narrowed, trun- 

 cated transversely, with a portion of firmer substance pro- 



* Translated by W. S. Dallas, F.L.S., from the ' Zeitschrift fur wis- 

 sensch. Zoologie,' Bd. xxxii. (1870) p. 4<;0. 



