668 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



like that of Rcemopis ; internal reprodajtive organs similar to those of 

 Hinido ; while the external male organ is more like that of Riemopis. 

 The genus differs from all the others, however, in the situation of the 

 genital orifices, in the form of the maxilhie, the number of plications in 

 the (Esophagns, &c. It includes one of the stoutest, largest, and most 

 powerful of the leeches hitherto described. 



Macrobdella DECORA Verrill. 



American Jouraal of Science, vol. iii, p. 138, fig. 4, February, 1872. 

 Hirudo decora ^^y, Loug's Second Expedition, vol. ii, p. 268, 1824; Diesiug, Sys- 

 tema Helm., i, p. 474; Leidy, Proc. Pliil. Acad. Nat. Sci., Idu8, p. 230. 



Body large, stout, broad, considerably depressed throughout ; in exten- 

 sion much elongated, and gradually tapering anteriorly; strongly annu- 

 lated. Length of the larger specimens twelve inches or more; greatest 

 breadth upward of an inch. Head rounded in front, the cephalic lobe 

 capable of considerable dilation, consisting, apparently, of five segments. 

 Ocelli, 10 : the first pair between the second and third segments ; the 

 second, on the third; the third on the fourth; the fourth pair on the 

 sixth, or buccal ; and the fifth on the ninth segment, or fourth behind 

 the mouth. Cephalic lobe rugose and wrinkled beneath, and with con- 

 spicuous longitudinal sulcatious, of which three, corresponding with the 

 maxillai, are deepest; posteriorly with a conspicuous semicircular fold, 

 surrounding and partially concealing the maxilhie when retracted, iuto 

 their fossae. Maxillie thick, very prominent, higher than broad ; outer 

 edge rounded in front, and finely and closely denticulate. Below each 

 maxilla, in the oesophagus, is a broad plication or fold, which often 

 divides into two a short distance beyond ; alternating with these are 

 three simple narrower folds, making six or nine in all. External male 

 organ prominent, stout, conical; the broad wrinkled base rising from the 

 twenty-fourth to the thirtieth segments ; the terminal portion smoother, 

 with six sulcatious ; the orifice small, with six lobes, opening in the 

 twenty-seventh segment. Female orifice also with small lobes, sur- 

 rounded by a slightly elevated area, formed upon the thirty-first and 

 thirty-second segments; posterior to these, there are four conspicuous 

 rugose elevations in a quadrangle on the thirty-sixth to the thirty-eighth 

 segment, and smaller ones on the thirty-ninth segment, with less marked 

 ones on two or three of the previous and following segments; corre- 

 sponding to these rugosities, there are well developed internal glands. 



The reproductive organs are here described from preserved specimens, 

 of large size, taken in the breeding season, in spring. At other seasons, 

 and in smaller specimens, these characters are not so obvious. Acetab- 

 ulum large, separated from the body by a well marked constriction. 



Color above, dark livid brown, or olive-green, with a median dorsal 

 row of about 20 to 22 bright or pale red spots, which are sometimes 

 obsolete, and a row of rounded black spots near each margin, corre- 

 sponding in number, and nearly in size, with the red ones. Lower sur- 



