J. E. LORD ON TWO NEW ROTIFERS. 79 



parallel, like the others ; but anteriorly the two central ones 

 approach each other, and then diverge to about the juncture of the 

 first and second central segments, where they are connected to each 

 other and the next pair by a transverse skin -fold ; posterior to 

 the dorsal spines these 4 ridges are broken up and connected by 

 cross folds in such a manner as to form a sort of parquet-Hke 

 pattern. On the ventral aspect these ridges are absent, but 

 there are faint indications of transverse plications. On the 

 anterior dorsal edge there are two conical spines close together, 

 with their apices forwards ; and on the extreme lateral edge, but 

 just below the anterior margin, there are two low spines, which, 

 on the extension of the animal, are at right angles to the body ; 

 and between each pair of ridges there are prominences, more or 

 less marked, which vary considerably in different individuals, 

 sometimes almost approaching spines in character. The anterior 

 ventral edge is excavated in a curved manner, and one or even 

 two pairs of low spines may sometimes be seen on the shoulders, 

 in a line with the lateral spines, and like them, below the 

 anterior edge, and at right angles to the ridges ; but these are, 

 I beUeve, only temporary. I have seen individuals entirely 

 without them, while perhaps the next had either one or two 

 pairs. Just behind the median line there is a transverse row 

 of 8 strong, rough spines, with acuminate points, diminishing 

 somewhat in size as they approach the sides ; occasionally an 

 extra pair may be visible, and as I saw several specimens with 

 this extra pair, I w^as led in the first instance to describe the 

 species as having ten spines in the row, but they are only 

 temporary, and may be seen gradually to melt away upon the 

 extension of the animal. Indeed, the formation of these 

 temporary spines seems to be a peculiarity of this species, and 

 may readily lead to error. I have seen a specimen with a 

 complete row of these spines anterior to the permanent ones, 

 another with spines posterior to them ; but in both cases they 

 vanished while under observation. The fact is, that, owing to 

 the thickness of the integument and the acuteness of the ridges, 

 these temporary spines are liable to be formed on any part of the 

 trunk, whenever contraction takes place. The spines are on the 

 ridges, and are indeed a continuation of them, as may readily 

 be seen either on a dorsal, but especially on a lateral view. 

 Immediately behind the spines there is a deep rounded 



