562 WILLIAM BLAXLAND BENHAM. 



reference to this worm. He, however, mentions Allolobo- 

 phora dubiosa as occurring with C. lacuum, so that, pre- 

 sumably, they are one and the same animal. But with all 

 these figures no general view of the worm has been given. 



My thanks are due to Professor Ray Lankester, not only for 

 these worms, but also for allowicg me to translate Dr. Orley's 

 paper, so that I could corroborate or comment on his observa- 

 tions, and fill in details which he has left untouched. I am 

 quite aware that a great deal more still remains to be done in 

 reference to the anatomy and histology of Criodrilus, but I 

 think the following, taken with the description of the previous 

 observers, forms a fairly complete account of its anatomy. 



External Characters. — I have nothing to add to Orley's 

 statements as to the length and number of somites of the worm ; 

 my specimens are all preserved in strong spirit, and are there- 

 fore greatly contracted ; they are much coiled and twisted and 

 had to be soaked in weak alcohol before they could be con- 

 veniently dissected. A deep groove traverses the dorsal surface 

 posterior to somite l; the ventral surface is rounded, and the 

 sides are more or less vertical (PI. XXXVIII, fig. 12). 



The prostomium is distinct, and its terminal pore has 

 been figured by Vejdovsky (loc. cit., pi. xiii, fig. 12). The 

 anterior somites are longer than the posterior ones, and are not 

 so prominently quadrangular in section. On the ventral surface 

 of somites ix, x, xi, xii, and xiii, there are prominent rounded 

 papillae, in which the ventral setse are inserted. 



The structure of the epidermis is to a certain extent figured 

 by Vejdovsky (loc. cit., pi. xiv, fig. 3). It consists of narrow 

 columnar cells with oval nuclei; their inner ends seem to 

 diverge and between them are seen small rounded cells with 

 rounded nuclei (PI. XXXVIII, fig. 17, c), which Vejdovsky 

 considers as young epiderm cells. Goblet cells are very rare ; 

 they are narrow cells filled with granular matter, with the 

 protoplasm and nucleus at the inner ends. As the worm 

 lives in water the necessity for secreting mucus would not be 

 so great as in Earthworms, properly so-called, and hence the 

 mucous cells are few and far between. The capillary loops of 



