250 FRANK IE. BEDDARD. 
The above resemblances are in structures which are, with 
the sole exception of Moniligaster, confined to the aquatic 
Oligocheta. Besides these, the genus Alluroides departs 
from the usual structure of the terrestrial Oligocheta in a few 
other points, viz. : 
1. There is no gizzard, no calciferous glands, and no typhlo- 
sole. 
2. The nephridia are deficient in the anterior segments. 
3. There is no subnervian vessel. ; 
These points do not absolutely distinguish the terrestrial 
from the aquatic Oligocheta, but they occur in a few of the 
former while characteristic of the latter. For example, there 
is no gizzard in certain species of Microscolex; Ponto- 
drilus has no calciferous glands, &c. 
The points in which the present genus resembles the terres- 
trial Oligocheta are by no means numerous. They are as 
follows : 
1. The segments occupied by the clitellum. 
2. The position of the male pores, and the fact that the sperm- 
duct traverses several segments on its way to the external pore. 
3. The situation of the ovaries in Segment x1it. 
In addition to these, there are some points in which Allu- 
roides agrees with earthworms to differ from the majority of 
the lower Oligocheta. The sperm masses in Alluroides are con- 
- fined to the 10th and to the 11th segments; it is the rule among 
the lower forms for the sperm-sacs to extend much further 
back. The testes being limited to the 10th segment is rather 
unusual among earthworms. When there are but a single pair 
of these gonads they are, as a rule, in the following segment. 
Among the Lumbriculide the testes are in the 9th segment, 
or, as in Rhynchelmis—and possibly in other genera,—in the 
9th and 10th. However, in Phreoryctes the testes are in 
Segments x and x1, but here the sperm-ducts open on to the 
exterior in the following segments. The same is the case with 
the nearly allied Pelodrilus.! 
1 « Anatomical Description of Two New Genera of Aquatic Oligocheta,” 
‘Trans. Roy. Soc. Hd.,’ 1890. 
