I02 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



1. The anterior vacuoles in the muscular layers of the 

 body-wall, which enable the body to suddenly expand and to 

 cling to the burrow. 



2. The caudal zone which partly serves the same purpose 

 and which also enables the worm to quickly perceive the 

 approach of enemies. 



3. The corkscrew-like twist of the posterior portion of 

 the body, which enables the worm to more readily cling to 

 the soil. 



4. The auditory cells in the epidermis. 



5. The intra-typhlosolar canals, which enable the typh- 

 losole to evacuate itself into the intestine. 



6. The quincuncial arrangement of the posterior setae, 

 enabling the worm to cling to the burrow with greater 

 tenacity. 



Septa. — (fig. 9.) There are especially thickened septa. 

 The one furthest anterior is found between somites III and 

 IV, and therefore bounds the posterior surface of the 

 very large suprapharyngeal gland. This septum is as thick 

 as any of the posterior ones. No such septum is figured 

 by Horst (17, fig. 33), and this further strengthens me in 

 the behef that the specimens he studied belong to a differ- 

 ent species from mine. The septa which should be separat- 

 ing IV/V and V/VI are absent, but the following septa are 

 greatly thickened. There is no septum between IX and 

 X, a character which is possibly of generic importance. 



SpermatheccB. — (figs. 8, 11.) The spermathec^e of 

 Pontoscolex corethrurus have more than once been wrongly 

 located, and nowhere do I- find it expHcitly stated where 

 and how they are situated. The most important character 

 of spermathecse generally is the position of the pores. The 

 pores may be either preseptal or postseptal, and the main 

 body of the spermathecae is situated either in the same somite 

 as the pores, or in a somite anterior or posterior to the somite 

 containing the pores. Beddard's statement that the sper- 

 mathecse are found in somites VI, VII and VIII has already 

 been referred to in this paper, Horst (17) in his latest 



