ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 231 



The author next describes the processes of division, which seem 

 to be of a much more primitive character than in G. pardalts ; all 

 individuals which consist of twenty or more segments are capable of 

 division ; there are no preliminary phenomena of gemmation, no zone 

 of gemmation as in C. pardalis, but only a slight constriction of the 

 integument, which gradually becomes more and more pronounced ; 

 the two daughter forms are at first without any head or anus re- 

 spectively, and it is only some time after the constriction that these 

 organs begin to be formed. They may give off fragments of one to 

 three segments which have neither head nor anus, and are no longer 

 capable of division, or pieces of five or sis segments which may again 

 divide and give rise to fragments similar to those already mentioned. 

 Lastly, the daughter form with the primary head is capable, after the 

 production of a secondary anus, of giving off the terminal portion, but 

 it is not known whether the other half of the parent form is capable of 

 a similar action. After discussing the phenomena of division which 

 he has observed, and comparing them with what is known in other 

 forms, the author passes to the affinities and systematic position of 

 Ctenodrilus. He regards it as a " collective type " which stands near 

 the point of union of the Oligocheeta and Polycha^ta, but, as in the 

 case of Polygordius, we can hardly, as yet, assign to it a definite and 

 fixed position in the zoological system. While it has, no doubt, an 

 alliance with the Polygordiidse, it has some special affinities to the 

 Oligoch^etous Naids, and other characters in which it as much 

 resembles the Polychaeta as the Oligochseta. 



Manyunkia speciosa.* — Under this barbarous name, J. Leidy de- 

 scribes a new fresh-water annelid closely allied to Fabricia. The tube 

 is composed of very fine particles, cylindrical, sometimes feebly an- 

 nulated. The tubes are formed separately, or a few together, and they 

 measure from 2 to 4 lines in length, and 1/5 to 1/4 of a line in width. 

 The mature worm is 3 to 4 mm. long, and 1/4 mm. in breadth, and con- 

 sists of twelve segments, including the head ; it is of a translucent olive- 

 green colour ; the head is surmounted by a pair of lateral " lopho- 

 phores," which support the tentacles. The seventh segment is twice as 

 long as any of the others, and has an abrupt expansion at the fore-part, 

 which suggested the production of a head prior to the division of the 

 worm ; gemmation, however, has not been observed. The number of 

 tentacles varies with the age of the worm, but there are generally 

 eighteen on each "lophophore " in a mature specimen ; they are ciliated, 

 and in all respects bear a close resemblance to those of the Polyzoa ; 

 they have various functions, and may be as justly called tentacles as 

 cirri. At their base are six or more brownish pigment-spots, which 

 resemble but have not the constitution of eyes. The segments behind 

 the head are provided with a fascicle of locomotive setae, some of which 

 are shorter than the rest ; there are from four to ten in each fascicle. 

 The setse have the form of a long straight rod, with a blade which 

 terminates in a long filament ; some of the posterior segments have 



* Proc. Acad. Nat. Sci. Philad., 1883, pp. 204-12 (1 pi.); and see E. Potts, 

 ibid., January 22, 1884. 



