The Craspedosomatidse of North America. 63 



The above is a translation, partly rearranged, of the description 

 •given in the ' Etudes.' It seems to have been based on one fe- 

 male specimen. The authors add the following remark : 



'• This species is evidently ver}' nearly related to Spirostrephon 

 ■csesioannulatus, Wood. But judging from the description and 

 figure, Mr. Wood's species seems not to have upon the sides a 

 row of tubercles larger than those of the dorsal surface. If Mr. 

 Wood had not given thirty-two segments for his species, instead 

 of thirty, we would not doubt that it should be included in the 

 genus Chordeuma or Craspedosoma. Our species approaches 

 Craspedosoma, Leach, in the form of the gnathochilarium, and 

 the development of the piligerous tubercleSj and Chordeuma, 

 Koch, in the cylindrical form of the bod3^" 



BACTROPUS gen. nov. 



Eyes of numerous (27) prominent ocelli arranged in triangular patches. 



Antennte long and slender, third joint longest, nearly equalled by the fifth 

 (10:9), followed by joints 4, 2, 6, 7, 1. 



Mandibles with ten pectinate lamellae.* 



Promentum not disthict. 



Segments with lateral carinse represented by a gentle bulging of the sur- 

 face; not striate; setigerous tubercles obsolete, the setse short. 



Male genitalia simple, hamate. 



Ninth legs of male five-jointed and -with a small claw ; coxa much larger 

 than the other joints taken together. 



Segments of adult 30. 



This genus resembles Cleidogona in general appearance, but the 

 body is smaller and more slender. It also has characters in com- 

 mon with Pseudotremia, Trichopetalum, and Conotyla. From 

 Pseudotremia it differs in the better development of the eyes, be- 

 ing evidently an open-air creature; also in the lateral carinse nearl}^ 

 obsolete and the lateral surface not striate. It resembles Pseudo- 

 tremia and Cleidogona in the slight development of setigerous 

 tubercles and in the number of joints of the ninth male legs. 

 This last resemblance is, however, onh;- apparent, for the form 

 and function is very diff'erent. In Pseudotremia and Clei- 

 dogona the ninth legs are capable of use as clasping organs, 

 while in Bactropus, as in Trichopetalum, it is difficult to 

 nnderstand how the ninth legs could serve such a purpose. Bac- 



* The condition of the specimen was such as to make the number somewhat 

 xmcertain. 



