GENUS PETALOTRICHA. 627 



Dictyocysta acuminata, Ehr. 



Lorica oblong, campanulate, acuminate posteriorly ; the distal border 

 truncate, widely expanded, perforate by a series of long narrow lacunae. 

 Length 1-432", breadth 1-576". 



HAB. Salt water : Newfoundland, among phosphorescent surface- 

 skimmings. 



GENUS II. PETALOTRICHA, S. K. 



(Greek, petalon, petal ; trichos, hair.) 



Animalcules free-swimming, excreting and inhabiting imperforate 

 corneous loricae ; enclosed body conical or campanulate, attached to the 

 fundus of the lorica by a retractile peduncle ; ciliary system restricted to 

 the excavate distal region, consisting of a series of larger marginal motor 

 cilia, which are developed upon petaloid or lappet-like prolongations of 

 the peristome-border, and an internal series of short vibratile cilia, which, 

 starting from the interior of the disc, follow about twenty curved lines 

 tangential to the margin of the peristome, and which are continuous at the 

 peripheiy with the external motor series ; oral aperture eccentric, continued 

 into a pouch-like pharynx, which stands out separately from the walls of 

 the body, and into which several of the rows of cilia of the disc are pro- 

 longed ; anal aperture located near the insertion of the peduncle. Inhabiting 

 salt water. 



This genus is provisionally instituted by the author for the reception of the two 

 species referred to the genus Tintinnus by Professor Fol,* under the titles of 

 Tintinnus ampulla and 7! spiralis. The restriction of the cilia to the distal region, 

 added to the abnormal disposition of these appendages, separates these species in a 

 marked manner from the typical members of the genus as defined in this volume, 

 and apparently indicates their nearer zoological position to the genus previously 

 described. 



Petalotricha ampulla, Fol. sp. WOODCUT, p. 628, FIGS, i AND 2. 



Lorica ovoid, terminated posteriorly by a slight projection in the form 

 of a point, widely open above, where an expanded funnel-like portion is 

 superposed upon the ovoid part ; the widened portion composed of two 

 zones, of which the superior is more turned out than the inferior one ; a 

 slight circular projection, notched into the likeness of an arcade, developed 

 on the inner surface along the boundary between the two zones ; body of 

 animalcule apparently smooth ; peristomal cilia arranged in twenty-four 

 curved lines, produced from the interior towards the margin of the disc. 

 Length of lorica, 1-280". 



HAB. Salt water : Villefranche-sur-Mer. 



The above diagnosis is reproduced verbatim from Professor Fol's description of 

 his so-called Tintinnus ampulla, to which is herewith appended an abstract of his 

 elaborate description of the oral and ciliary systems. With reference to the notched 



* ' Archives des Sciences Physiques et Naturelles,' torn, v., 1881. 



M 



