vni, D, 4 Wharton: Some Philippine Thalassemx 245 



of the groove on the ventral side. In formalin both the body and 

 proboscis become nearly colorless. 



There are 3 pairs of unusually small nephridial sacs, of which 

 the posterior pair is always the largest. In a specimen 7 cm. 

 long the sacs measured, respectively, 2, 3, and 5 mm. in length. 

 The anterior pair always lies in front of the ventral setae, the 

 second pair about an equal distance back of the setae, and the 

 second and third pairs are always about twice as far apart as 

 the first and second. Each sac bears 2 spirally twisted ne- 

 phridia which enter the sac by a common opening on the dorsum 

 just within the attachment of the sac to the body wall. 



The anal trees are long, brown in color, and open into the 

 rectum on the left side. Lying between 



them is a small spherical diverticulum of J/r — ■* 



the rectum (fig. 1). The anal trees are /^^^^^.T "^ 

 covered with short ciliated funnels which / J^^^^^}^^^C~*' 

 are plainly visible under a magnification / //^ //A^^rvV "^' 

 of 50 diameters. I (j /nl L.-A-jf'^'' 



The alimentary canal has a total length Ul I ilyi iT.^^'''^, 

 of about 36 cm, in the largest specimens. \\\\lH/p'-h.'dZ^l.^^ 

 It may be divided into 5 parts — cesoph- \\WaQ>^^^^f^X^^ 



agus, crop, gizzard, intestine, and rectum, ^^^n^ /. -'' 



This form differs from the majority of ^^'^2?^-- ■■—■■'■ 



echiuroids in that there is no muscular fig. i. Diagram of the inter- 

 pharynx, the mouth opening directly into "^^ ""^^"^ °* Thaiassema 



,, , . n 1 1 , . I . sorbillans Lampert. pr, 



the thm-walled oesophagus, which is a proboscis; «e. nephndiai 

 straight tube about 1 cm. long. The ^^^= "«*' esophagus: «•. 

 "heart" is attached to its dorsal surface, testine; c. int. iioUatcrai 



and the two connecting blood vessels pass intestine; r, rectum; d. di- 



1 -J- T-. 1 • 1 iT at J ,1 ji vertlculum ; at, anal treed; 



around it. Behind the heart, the crop „, nerve. 

 forms a loop, which when straightened 



out is about 1 cm. long. From it the gizzard, or "midgut," 

 runs transversely to the left. This organ has a length of 

 about 2 cm., and is smaller in diameter than the crop. At 

 the end of the gizzard the canal widens greatly, the walls 

 become much thinner, and the intestine may be said to begin 

 at this point. The intestine is divided into two parts. The 

 first part has a diameter of from 4 to 5 mm., a length of 

 about 15 cm., and bears the collateral intestine throughout its 

 length. The latter organ is about 1 mm. in diameter, and its 

 walls are thicker than those of the main part of the intestine. 

 Both of its openings into the intestine may easily be found. The 

 second part of the intestine, which begins at the end of the collat- 

 eral intestine, is a little longer than the first part, but is much 



