6 10 ORDER HETEROTRICHA. 



denticulate transverse annulations, the remainder of its surface perfectly 

 smooth ; enclosed animalcule as in Tintinnus inquilinus. Length of 

 lorica 1-192". HAB. Salt water : White Sea (Mereschkowsky). 



Excepting for the presence of the denticulate annuli at the anterior extremity, 

 the lorica of this species is indistinguishable from that of T. subulatus. 



Tintinnus mediterraneus, Meresch. 



Lorica transparent and homogeneous, urceolate, scarcely longer than 

 broad, abruptly narrowed in a neck-like manner anteriorly, not everted, the 

 posterior extremity obtusely rounded or terminating in an acute point ; 

 four or five closely approximated parallel linear annulations ornamenting 

 the neck-like portion. Animalcule not observed. Length of lorica 1-160". 



HAB. Salt water : Black Sea and Bay of Naples (Mereschkowsky) 



This species is figured and described by Mereschkowsky in company with 

 several other interesting marine types in the 'Annals and Magazine of Natural 

 History' for April 1881. The two forms of this species, distinguished respectively 

 by the rounded or acuminate termination of the posterior extremity of their loricas, 

 were obtained respectively from the Black Sea and Bay of Naples, and receive from 

 their discoverer the separate designations of Tintinnus mediterraneus var. pontica and 

 T. med. var. neapolitana. 



Supplementary Species. 



Quite recently, Professor H. Fol has contributed to the ' Archives des Sciences 

 Physiques et Naturelles,' torn, v., January 1881,* a memoir on the organography of 

 the genus Tintinnus. Among other important points, he therein maintains that the 

 oral ciliary system exhibits a far more complex structural plan than that of either 

 one or morp concentric circles or spiral revolutions, as represented by previous 

 authorities. In place of this he reports of two new Mediterranean species, Tintinnus 

 ampulla and T, spivalis, as examined by himself, that the cilia of the peristome are 

 all arranged in accordance with about twenty curved lines, which, starting from 

 the interior of the disc, become tangential to its margin, the longest and strongest 

 cilia being developed at the periphery. Presuming that such a structural plan of 

 the ciliary system as is described and delineated by Professor Fol of these two types 

 actually exists, the author is unable to regard them as eligible for admission into 

 the genus Tintinnus., the broad petaloid modification of the peripheral border, with 

 its associated cilia, being altogether distinct from what obtains in the typical 

 members of that genus as verified in so large a number of species by Claparede and 

 Lachmann and other recent observers, and as also certified by the author in the case 

 of Tintinnus subulatus. These two forms are hence provisionally referred to the 

 Peritrichous order in connection with the new generic title of Petalotricha. 



Professor Fol has further proposed to subdivide Tintinnus, as here defined, into 

 two subordinate generic groups with reference to the consistence of their pro- 

 tective loricae or tests. Following out this plan, he suggests the title of Tintinnus 

 for those forms only in which the test is entirely smooth and plane, and that of 

 Coniocydis for those species in which the test is more or less marked with trans- 

 verse striae and impregnated, especially in parts, with foreign mineral particles. 

 This suggested innovation is not, however, advocated in this treatise, the composi- 

 tion of the test being regarded by the author as a character entirely subordinate to 

 the structure of the animalcules by which they are fabricated. If, indeed, such a 

 distinction must be recognized, it would be also desirable to establish a third genus 

 for such forms as Tintinnus subulatus and T. Ussowi, in which the test or lorica, 



* This paper is translated by Mr. W. S. Dallas in the ' Annals and Magazine of Natural 

 History' for April 1881. 



