208 



THE AMERICAN MONTHLY 



[November, 



that may probabl_y be considered a 

 fresh-water variety of ,S. uricolata, the 

 two agreeing in essential characters, 

 excepting the possession of the elas- 

 tic neck of the sheath ; but more 

 careful study may yet demonstrate 

 the existence of even that peculiarity. 

 My impression is that S. urccolata is 

 no more restricted to sea-water than is 

 Thuricola valvata. 



Having, in early spring, also col- 

 lected Salpingceca fusiformis, S. K., 

 from a very small -and shallow pool 

 that speedily evaporated, it may be 

 worth recording that the lorica of each 

 individual was attached to the confer- 

 void filament through the medium of 

 a conspicuous disk-like enlargement, 

 and not directly by the acute tip of 

 the sheath, as figured by the latest 

 authority on the subject. It has not 

 been found elsewhere and was prob- 

 ably a local variety. A form corres- 

 ponding with Kent's description and 

 figures is not rare. 



Trenton, N. J. 



A New Vorticella. 



BY DR. ALFRED C. STOKES. 



Though there are already thirty- 

 nine species of Vorticellce, it is neces- 

 sary to make the number an even 

 forty by the addition of a presumably 

 undescribed form that I have recently 

 found in some abundance. On account 

 of its peculiar and well-developed ex- 

 ternal investment I have named it 

 Vorticella vcstita. 



V. vesfita, n. sp. — Body soft and 

 plastic, broadly campanulate, widest 

 at the anterior margin, constricted 

 beneath peristome border and poste- 

 riorly rounded at its junction with the 

 pedicle ; when contracted, subsphe- 

 roidal. The whole cuticular surface 

 is covered by a conspicuous cellular 

 coating which gives the superficial 

 aspect a minutely reticulated appear- 

 ance, and the external margin a finely 

 crenated outline when seen in optical 

 section. This investment is formed 

 of a single layer of cells arranged in 



equatorial series, the upper and lower 

 cell-walls being equidistant in each 

 row throughout the whole length of 

 the body. The cells themselves are 

 as colorless as the animalcule and as 

 transparent, their contents being in- 

 visible liquid usually containing many 

 dark-bordered, actively moving gran- 

 ules. When the creature is in a weak- 

 ened or dying condition the cell con- 

 tents are so increased in quantity that 

 the cells become extended and bubble- 

 like, the zooid then resembling a mass 

 of froth. 



The peristome border is but slightly 

 everted. The vestibular bristle is 

 well developed and conspicuous. The 

 contractile vesicle pulsates at intervals 

 of twelve seconds. The nucleus is 

 band-like, curved, and remarkably 

 long, one arm extending across the 

 body anteriorly for almost its entire 

 width, then bending and curving for 

 nearly an equal distance along the 

 ventral side of the zooid. 



The pedicle is from six to seven 

 times the length of the body, and 

 when retracted forms about seven 

 coils which exhibit transverse stria- 

 tions or wrinkles, particularly notice- 

 able as it is extending. The muscular 

 thread is roughened at irregular inter- 

 vals by clusters of minute, rounded 

 elevations. 



Body -r^ly, inch in height. 



The species has thus far been taken 

 from but one locality, on an alga 

 growing in the Delaware and Rarilan 

 Canal, near this city. 



Trenton, N. J. 



Statoblasts of the Fresh-water 

 Spoiii^es. * 



PA' B. W. priest. 



Having lately been engaged in ex- 

 amining ihe statoblasts of the species 

 of fresh-water sponges at present 

 known, and being struck with their 

 marvellous structure and beautv, I 



* Finni Jourtuil of the Qiiekett Microscopi- 

 cal Club. 



