GENUS TINTINNUS. 605 



as long as the body ; peristome-field circular, excavate, its inner margin 

 bordered by several cycles of long, powerful adoral cilia ; contractile vesicle 

 anteriorly situated. Length of lorica 1-200" to 1-130". 

 HAB. Salt water : Norwegian coast. 



Transverse fission has frequently been observed by Stein in association with this 

 species, this phenomenon being heralded by the development around the centre 

 of the elongated body of the animalcule of a second girdle of powerful cirrose 

 cilia. The Tintinnus inquilinus of Ehrenberg represents two essentially distinct 

 animalcules ; the free-swimming type, obtained by him from the harbour of Copen- 

 hagen, only being identical with the present species. The second form, encountered 

 at Kiel, inhabiting a lorica which is permanently attached posteriorly to algae and 

 other objects, and which is alone represented in his illustrations of T. inquilinus* is 

 not a true Tintinnus and will be found described further on in connection with the 

 name of Tintinnidium marinum. The fine cuticular cilia of the present species, 

 clearly indicated in Claparede and Lachmann's drawing, have been accidentally 

 omitted by the artist in the accompanying reproduction of their figure. 



Tintinnus subulatus, Ehr. PL XXXI. FIG. 5. 



Lorica elongate-cylindrical, diaphanous, from twelve to fifteen times as 

 long as broad, terminating posteriorly in a long, sharp, and sometimes 

 slightly curved spine-like point, the anterior region ornamented with several 

 parallel transverse annulations, the front margin not everted ; animalcule 

 elongate, subcylindrical, having a very long, slender, retractile pedicle, 

 entirely enclosed within its protective sheath. Length of lorica 1-120". 



HAB. Salt water : abundant in the North Sea. 



It is possible, as already intimated by Ehrenberg, that the Vorticella vaginata of 

 O. F. Miillert is identical with this species, though at the same time the body of the 

 animalcule in the last-named type presents a more globose outline, and there is a 

 faint indication in Miiller's figures, though not referred to in the text, of the lorica 

 being attached posteriorly as in Tintinnidium, or an ordinary Vaginicola. To some 

 extent, again, the figures referred to recall the initial condition of Zoothamnium 

 arbuscula or Z alternans (PL XXXVII. Figs. 6 and 7), in which a single large 

 subglobose zooid surmounts the relatively thick transparent pedicle, the distal 

 extremity of which alone encloses the retractile filament, and bears consequently 

 no inconsiderable resemblance to a hyaline lorica. 



Tintinnus mucicola, C. & L. sp. PL. XXXI. FIG. 16. 



Lorica subcylindrical, mucilaginous, transparent, its surface somewhat 

 uneven, little over twice as long as broad ; body of animalcule ovate or 

 pyriform, occupying about one-third of the cavity of the lorica, retractile 

 pedicle very long, fixed to the bottom of the sheath and permitting the 

 animalcule to protrude considerably beyond its anterior margin. Length 

 of lorica 1-150". HAB. Salt water: Norwegian coast (C. & L.). 



It is rather doubtful whether this species is not rightly referable to the closely 

 allied sedentary genus Tintinnidium, and in that case would scarcely be distinguished 

 from Tintinnidium marinum. Claparede and Lachmann testify to its close resem- 



* ' Infusionsthierchen,' pi. xxx. fig. 2. 



t ' Animalcula Infusoria,' pi. xliv. figs. 12 and 13, 1786. 



