356 Transactions of the Society. 



of the lateral margins with the anterior dorsal margin, which is 

 remarkably short. The lateral sulcus is extremely deep in the 

 anterior third of the lorica, and is very shallow behind that. This 

 makes the portion of the anterior margin w^iich connects the ends 

 of the dorsal and ventral plates unusually long, at each side about 

 one-third of the entire width. 



The ventral plate is widest near the anterior angles, diminishes 

 backward, and usually has a scalloped margin. The segment pro- 

 jecting behind the dorsal plate is broad, rounded, and not very 

 prominent The margins of the toe are slightly undulate, and the 

 shoulder is not sharp. 



These structures, so complicated to describe, should be easily 

 understood from the figure. The outer dotted line is the scalloped 

 edge of the ventral plate. The inner dotted line indicates the 

 bottom of the sulcus, and merges towards the front in the afore- 

 mentioned ridges. 



Although the specific name is founded on the dots, this is not 



EXPLANATION OF PLATE XV. 



Fig. 31a. — Monostyla lunaris. Dorsal view. 



,, 316. Ditto. Posterior part of lorica. 



,, 32a. — M. amazonica sp. n. Dorsal view. 



„ 326. Ditto. Toe. 



,, 33a. — M. bulla. Dorsal view. 



,, 336. Ditto. Variety; toe. 



,, 33c. Ditto. Side view of toe. 



,, 34. — M. quadridentata. Dossal view. 



,, 35a. — M. bicornis Stenroos. Dorsal view. 



„ 356. Ditto. Toe. 



,, 36a. — M. piinctata sp. n. Dorsal view. 



,, 366. Ditto. Anterior part, showing dots. 



,, 36c. Ditto. Ventral view. 



„ 36d. Ditto. Toe. 



,, 37a. — M. obtusa sp. n. Dorsal view. 



,, 376. Ditto. Toe. 



,, 38a. — M. truncata. Dorsal view. 



„ 386. Ditto. Toe. 



,, 39a. — M. closterocerca. Dorsal view. 



„ 396. Ditto. Toe. 



,, 40a. — M. furcata sp.n. Dorsal vi»w. 



„ 406. Ditto. Toe. 



,, 41a. — M. hamata. Dorsal view. 



,, 416. Ditto. Ventral view. 



„ 41c. Ditto. Toe. 



,, 42a. — M. arcuata. Dorsal view. 



„ 426. Ditto. Toe. 



,, 43a. — M. decipicns sp. n. Dorsal view. 



„ 436. Ditto. Toe. 



,, 43c. Ditto. Side view of toe. 



,, 44a. — ilf. asjt/mmefnca sp.n. Dorsal view. 



„ 446. Ditto. Toe. 



,, 45a. — M. cochlcaris s^. n. Dorsal view. 



„ 456. Ditto. Toe. 



(All figures are magnified 260 diam.) 



