NO. 1160. LEECHES OF THE U. S. NATIONAL MUSEUM— MOORE. 553 



between tlie two secondary rings of annulus nineteen (tlie first of somite 

 XI). They are consequently separated by four small secondary annuli. 



The somites of the posterior region are hexamerous, but the three 

 primary annuli are easily recognized ; and the first and second of each 

 somite, except XII, are undivided at the margins, where they are occu- 

 pied by the paired respiratory vesicles. The vesicles, as in the species 

 to be described next, extend over the first and second primary rings of 

 each somite, though in many cases the second is only partly occupied. 

 Anteriorly the vesicles are collapsed and, except for their color, indis- 

 tinct, but posteriorly they become much more prominent. Traces of a 

 rudimentary fourteenth pair are found just anterior to the anus. 



The color i>attern of this species is interesting, and has probably 

 been derived from the breaking uj) and partial shitting of an annular 

 pattern, which still i^ersists to some extent in the anterior region. The 

 general color above is a rich bright orange anteriorly, becoming faded 

 to a pale yellow posteriorly, where it extends over much of the ventral 

 surface also. The ventral surface of the anterior region, the greater 

 part of the clitellum, and the head are of a pale ashy color, which spots 

 the dorsal surface also. These ashy spots show a distinct tendency to 

 become arranged in three longitudinal rows on the jjosterior region. 

 They are mostly large and of irregular shapes, and very nearly corre- 

 si)ond to the somites, but those of the middle series have shifted more 

 or less toward the posterior end and sometimes become confluent with 

 neighboring blotches. All are edged by a very narrow border of red- 

 dish brown. A few similar irregular blotches are seen on the ventral 

 surface. A small orange patch surrounds the male pore, and there is a 

 similar one on each side of the clitellum. On each side of the dorsal 

 surface of the head is a large bright orange spot, leaving a median ashy 

 area. In the figure the orange-colored parts are stippled, the ashy 

 plain. The hexamerous structure of the posterior somites is represented 

 only in XIX and XX, but the others are similar. 



The single specimen measures : 



inni. 



Length 13. 5 



Greatest breadth 4.2 



Length of anterior region 3 



Breadth at male pore 9 



Breadth of anterior sucker 1 



Diameter of posterior sucker 1.5 



Depth of posterior region of body 1 



Type. — Xo. 1314, U.S.X.M. Steamer Albatross. Locality unknown. 



lo. TRACHELOBDELLA RUGOSA, new species. 



(Plate XL, fig. 5.) 



The adult specimens of this species have the broad depressed form 

 shown in the figure: a young individual is terete, with the vesicles 

 appended to the sides of the body, and connected by a broad lateral 

 cutaneous fold lodging the marginal sinus, by the metameric enlarge- 



