NO. 2032. ROTATORIA OF WASHINGTON AND VICINITY— HARRING. 399 

 MONOSTYLA CRENATA, new species, 



Plate 36, figs. 4-6. 



In complete retraction the dorsal plate of the lorica is subovate, 

 the anterior margin being almost straight. The ventral plate is 

 oval, sUghtly narrower than the dorsal and projects but very httle 

 beyond it posteriorly; the anterior sinus is deep, rounded at the 

 bottom and has strongly curved sides. The lateral sulci are deep, 

 but narrow, the edges of the dorsal and ventral plate being nearly in 

 contact their entire length. The posterior sulcus is of moderate 

 depth. The lorica is not facetted. 



The second foot- joint is slightly heart-shaped, excised in front, 

 where it articulates with the rigid first jomt, which is oval in outline. 

 The toe is nearly three-fourths as long as the body, moderately stout 

 and* shghtly decurved at the base; the claw is very small. The 

 mucus duct is without constrictions. 



The ventral plate is markedly convex and the dorsal very strongly 

 so; owing to this, as well as the difference in outline, a considerable 

 opening remains between the two plates of the lorica, when the head 

 is completely retracted. 



Total length, 190 /x; length of dorsal plate, 108 n, width, 88 /z; 

 length of ventral plate, 118 //, width, 80 //; depth of ventral sinus, 

 20 p.; distance between inner edges of lateral sulci at their widest 

 point, 68 fi, at narrowest (posterior), 42 pt; length of 'toe, 72 /i, of 

 claw, 8 p; greatest depth of body, 60 /<. 



Type.— Cat. No. 16521, U.S.N.M., is from Kenilworth, District of 

 of Columbia; the animal is locally the most abundant species of the 

 genus, and seems to be widely distributed; it is common in collections 

 from the Bureau of Fisheries station at San Marcos, Texas, and also in 

 the collections of the Panama Biological Survey. Mr. James Murray 

 informs me that he finds it in Australasia. 



MONOSTYLA SYLVATICA, new species. 

 Plate 35, figs. 1-3. 



In complete retraction the dorsal plate of the lorica is nearly 

 circular and has a shallow, rounded anterior sinus. The ventral 

 plate is ovate and but four fifths the width of the dorsal; the anterior 

 sinus is of moderate depth, rounded at the bottom and with nearly 

 straight sides. The lateral sulci are completely obhterated in con- 

 tracted specimens, so that the dorsal and ventral plates appear to be 

 jomed by flat plates. The posterior sulcus is shallow. The lorica is 

 without either dorsal or ventral markings. 



The first, immovable, foot joint is oval, the second heart-shaped; 

 the shghtly decurved toe is about half the length of the body and has 

 a small claw. 



