1894.] o6J [Stokes. 



into two regions, a posterior, inflated, obovate portion, tapering to the 

 pedicle, and an anterior region, subcylindrical, somewhat exceeding the 

 posterior region in length, its lateral margins parallel, the anterior aper- 

 ture circular, its borders everted ; pedicle usually exceeding the lorica in 

 length ; enclosed animalcule freely motile within the lorica, at times 

 situated exclusively within the frontal, neck-like portion, at others 

 extending into the anterior region of the posterior part of the sheath ; 

 when disturbed retreating into the posterior region, and advancing to the 

 frontal portion when its fright has passed, the sarcode then completely 

 filling that part of the lorica and taking its shape. Length of lorica x^V? 

 inch. Hab. — Standing water from the Morris and Essex canal, New 

 Jersey. 



The water in which this beautiful and characteristic form was found 

 was taken from the canal late in the autumn of 1891, by Mr. S. Helm, of 

 New York city, and by him sent to me. It remained on my table until 

 February 17, 1892, almost unnoticed, except that a little water was occa- 

 sionally added to supply that lost by evaporation. On the date last men- 

 tioned the animalcule was found in some abundance, attached to various 

 submerged fragments and in company with a profusion of Salpingceca 

 gracilis J. Clk., a form which it somewhat resembles, and near to which 

 it should be classified. 



Prorocentrum himatum, sp. nov. (Fig. 3). — Body ovate, less than 

 twice as long as broad, smooth, depressed, the lateral borders slightly 

 flattened, the posterior margin evenly rounded and obtusely pointed ; 

 dorsal surface convex ; ventral aspect somewhat flattened, bearing on its 

 frontal margin a stout, anteriorly projecting, obtusely pointed, often 

 colorless process, which is bent hook-like almost at a right angle, directed 

 towards the left-hand side and slightly excavated dorsally, thus exhibiting 

 a ledge like or shelf-like projection towards that aspect of the body ; 

 frontal border truncate, surrounded, witbin the margin, by an annular 

 groove, the right-hand and left-hand ventral continuations of which 

 extend obliquely along the adherent posterior prolongation of the frontal 

 process and unite to form a subcentral, longitudinal ventral depression ; 

 anterior flagellum spirally undulating, taking its origin from within the 

 ventral portion of the anterior groove, on the left-hand side of the 

 posterior prolongation of the hook-like process, and extending round the 

 frontal border into the groove on the right-hand side of the frontal pro- 

 jection ; ventral flagellum long, trailing, vibratile, taking its origin from 

 near the central region of the ventral groove ; nucleus subspherical, 

 located near the posterior extremity, often with an apparently amylaceous 

 corpuscle on one side and near it. Chromatophores linear, elongate, 

 vermicular or variously curved. Length, ^Jg^ inch. iZa6.— Brackish 

 water from a salt marsh on Coney Island, N. Y. Movements rotary on 

 the longitudinal axis. Abundant. 



This form was collected and sent to me by Mr. H. C. Wells, of Short 

 Hills, N. J. 



