Art. 12. AN EARTHWORM OF THE GENUS DIPLOCARDIA SMITH. 5 



one. In D. keyesi Eisen describes 7/8, 8/9, and 9/10 as mncli thicker 

 than the body wall; 5/6 is said to not join the body wall, but is 

 described and figured as forming a sort of sac including the pharyn- 

 geal region of the esophagus. He found no trace of a septum an- 

 terior to 5/6. 



Two well-developed gizzards are present in 5 and 6. Tlie pharyn- 

 geal region and the esophagus as far back as 13 are not noticeably 

 different from those of other species. The walls have an extensive 

 blood supply in 9^13 through numerous branches of the supra- 

 intestinal vessel. The walls of 14 and 15 are also highly vascular. 

 They have several connections with the dorsal vessel and have a few 

 low longitudinal folds of the epithelial layer. In the type specimen 

 there is a considerable dilation of these two somites, but not in the 

 paratype. The contracted part of the esophagus beginning with 16 

 has no such extensive blood supply as has the part anterior to it, and 

 has a diameter only about one-third as great as that in 19, where the 

 expanded intestine begins. The walls of the latter have an exten- 

 sive blood supply. Eisen makes no reference to the place of the 

 beginning of the widened intestinal part in his original description 

 of D. keyesi^ but a figure in that paper conforms with the brief state- 

 ment in each of the two later papers — " sacculated intestine in XV." 

 Eisen states that no typhlosole is present in that species, but the new 

 form has one that is perfectly obvious. 



The dorsal and supra-intestinal vessels in a few somites of the 

 type specimen are not included in the piece that was sectioned, but 

 there is nothing to indicate that the character and relations of these 

 vessels and of the hearts in the type specimen differs from those 

 found in the paratype. The dorsal vessel has not been found to be 

 double in any part of its course. The supra-intestinal vessel is a 

 definite, distinct trunk from the middle of the ninth to the middle 

 of the thirteenth somite. The " hearts " of 10 to 12 are much larger 

 than the others, and are of the dorso-intestinal type, regularly found 

 in the genus, while those of 7 to 9 are of the dorsal type. In his 

 description of D. keyesi^ Eisen writes simply of vessels in 7-12 con- 

 necting the doreal and ventral vessels, and states that those of 10, 11, 

 and 12 are larger and of " the form of so-called hearts." At the 

 time that he wrote it had not been noticed that the posterior pairs of 

 hearts in Diplocardia. are of the dorso-intestinal type. 



The nephridia are meganephric and the first pair is in the second 

 somite. The nephridial ducts with nephridiopores, but slightly dorsad 

 of seta line d have a course which is slightly ventrad and posteriad 

 through the layer of circular muscle fibers in the body wall to a level 

 of seta line d, and then through the layer of longitudinal muscle 

 fibers to the coelome. Their course in this latter layer is between the 

 two bands of fibers which further posteriad separate and extend on 



