338 C. F. ROUSSELET OX THE ROTATORIAN FAUNA OF BOSTON. 



in the same water ; but the subsequent discovery of the 

 characteristic differences in the structure of the lorica obliges me 

 to give it a new specific name. Moreover, a number of the 

 examples were carrying an egg on the postero-ventral side, 

 showing that they are mature animals. 



The internal anatomy was not specially studied, but appears to 

 be normal and the same as in other species of the genus. 



The specific diagnosis of Xotliolca hostoniensis may be 

 expressed as follows : 



Lorica ovoid, greatly produced behind into a long spine ; four 

 occipital spines, the left median spine very long, the other three 

 small, of about equal size. 



Total length of lorica, 360 /x (.\ in.); long anterior spine, 

 136 fi (j^q in.) ; posterior spine, 122 /x (-^-^in.). 



Oecistes, sp. ? 



In the same water I observed a free-swimming tube-dweller 

 of the genus Oecistes, which is unlike any species that I am 

 acquainted with or that I have seen described. Unfortunately 

 my observations were too hurried, and the preservation en bloc 

 of the material did not produce sufficiently well-preserved and 

 expanded specimens to enable me to give a good description 

 of it. 



The animal inhabits a tube perfectly cylindrical in shape, open 

 at the anterior end, and rounded and closed posteriorly, 3-40 /x 

 ( T V in.) long and 75 /x (3^ * n w ^ e - The anterior two-thirds 

 of the tube is semi-opaque by being covered with brown material 

 in the form of rodlets ; the density of the material diminishes 

 posteriorly, leaving the posterior third of the tube quite clear. 



Of the corona of the rotifer inhabiting this tube I can only 

 say that it is nearly circular with a well-marked notch on the 

 ventral side. Two fairly long cylindrical ventral antennae were 

 readily seen in contracted specimens. The body of the Oecistes 

 is 238 /x ( T ^ T in.) long when partially contracted, cylindrical, 

 tapering posteriorly into a short foot, which appears always 

 fixed to a short, thin, rigid stalk .3-1 /x ( T f^j in.) long, the posterior 

 end of which lies free in the tube. Two red eyes, wide apart 

 on the corona, were observed. 



This being all the description I can give of this probably new 



