172 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 52. 



specimens were anesthetized before killing. In some of the speci- 

 mens, the anterior margin of the clitellum is on 21 while in others it 

 is on 20, aa is approximately |6c., and ab is greater than cd. 

 There are about 40 longitudinal partitions in the calciferous gland. 



HELODRILUS (BIMASTUS) GIESELERI var. HEMPELI Smith. 



Helodrilus (Bimastus) gieselerivax. hempeli Smith, 1915: 551. 



Length, 5-8 cm. Somites, usually 105-115 in complete specimens. 

 Color, brown-red, distributed fairly uniformly on the dorsal half of 

 the worm; the ventral half is without pigment. Posterior to the 

 clitellum, aa : ab : Ic : cd : dd = 20 : A : IQ : 3 : 52, approximately. 

 Chtellum, 22-29 or ^30. Septa 6/7, 7/8, and 13/14, slightly thicker 

 than others, none much thickened. Longitudinal partitions of the 

 calciferous gland, about 40 in number. Sperm sacs and sperma- 

 thecae, as in the typical form. 



These worms are ordinarily found under the bark of decaying logs 

 or in the rotten wood. They are present in collections made in 

 Florida (Monticello), Ohio, Illinois, Kansas, and Texas. 



A comparison of the above description with that of H. tumidus will 

 show their great similarity in most respects. The only significant 

 differences are in the number of somites, the intervals between the 

 setae, and the shape of the body as shown in cross section. We do 

 not know how many specimens Eisen had as a basis for his state- 

 ments concerning the number of somites in H. tumidus; "circiter 40," 

 in the text; and 50, as given in the table. If there were several 

 specimens, we can not safely assume that they were aU mutilated 

 and thus explain the presence of less than haK the number of 

 somites, normal to H. gieseleri and H. g. hempeli. The spacing of 

 the setae in the setal bundles, ah and cd, is subject to much variation 

 in the different bundles in the same worm, and it is quite possible to 

 get formulae from adjacent somites that are materially different. 

 Care is necessary to have the setal formula show average conditions. 

 The specimen of H. tumidus shows almost exact equality between 

 ah and cd, on the average. There is great uniformity in the relation 

 of ah = about ^cd in all of the H. gieseleri and H. g. Tiempeli material 

 examined by the writer. The tetragonal form of the body is very 

 noticeable in H. tumidus, as stated by Eisen. It is no more notice- 

 able in the other forms under discussion than in the average 

 Lumbricidae. It seems more reasonable to assume that this differ- 

 ence is due to structural conditions rather than to mere differences 

 in methods of preservation. On the whole, it seems safer to await 

 more complete knowledge of the earthworms of the region where 

 H. tumidus was collected before uniting it with //. gieseleri hempeli. 

 If such union is found desirable, then H. gieseleri typica would reason- 

 ably be treated as a variety of H. tumidus. 



