ANNELID GENUS CAMBARINCOLA HOFFMAN 311 



The existence of Pierantoni's old name Branch iobdella americana 

 constitutes the major threat to the vahdity of mesochorea. So far as 

 the description goes, it apphes quite well to mesochorea, macrodonta, 

 philadelphica, and perhaps chirocephala. Reference of americana to 

 the European genus Branchiohdella is surely based upon nothing more 

 than Pierantoni's assumption of generic identity — americana being 

 proposed prior to Ellis's establishment of the genus Camharincola . 

 As no material (aside from a single collection from New York reported 

 by Goodnight) of a branchiobdeUid with only one pair of testes has 

 ever been seen from North America, and since recent morphological 

 studies indicate that Branchiohdella is doubtless a Palearctic genus, I 

 do not think that B. americana will prove to be other than some wide- 

 spread and well-kno^vn species of Camharincola. Pierantoni's types 

 came from Texas and North Carolina and probably represent at least 

 two species. Restudy of his slides and selection of a lectotype for 

 the species may indeed show the priority of the name americana over 

 mesochorea, but until this can be accomplished it is desirable to have a 

 name available for the designation of this distinctive species. 



MACROCEPHALA GROUP 



The two species presently comprehended by this heading present 

 such an array of basic similarities that their close relationship seems 

 indisputable. One of the species is endemic to the Snake River 

 drainage of Wyoming and Idaho, while the other is apparently localized 

 in central Kentucky. Although the final word concerning the knowl- 

 edge of this relationship remains to bo written, some preliminary 

 remarks may be of interest. 



The group is characterized by (1) large size of body, and especially 

 of the head, (2) a distinctive form of peristomial tentaculation, (3) 

 short body segments of considerable diameter, having the effect, in 

 the genital segments, of compressing the sex organs into a vertical 

 alinement, (4) a large, globose bursa and relatively long ejaculatory 

 duct, and (5) a very long spermiducal gland, entally bilobed at the 

 entry of the deferent ducts. 



Such characters are best appreciated by reference to illustrations, 

 but attention is called in particular to the form of the peristomium. 

 In most "tentaculated" species of the genus, the dorsal half of the 

 peristomium is produced into four marginal lobes of gi-eater or lesser 

 dimension, the culmination being reached in C. fallax in which the 

 lobes are fairly long and slender. In tlie present group, however, 

 the tentacles are much more slender, and are submarginal in origin, 

 resulting in a completely different appearance (see figm-es 15 and 18). 



