16 PROCEEDIiSrGS OF THE NATIONAL MUSEUM. vol. 60 



Tlie dorsoventral muscles are chiefly isolated bundles along the 

 sides of the thorax and genital segment, which assist in the passage 

 of the eggs along the oviducts. 



Digestive canal. — The general form and position of the digestive 

 canal have already been stated. In Lemanthro'pus the esophagus 

 passes inward and backward straight to the ventral surface of the 

 stomach, which it enters close to the anterior end. In Nemesis and 

 DichelesthiuTn there is a sharp bend or flexure in the esophagus, 

 the outer three-fifths pointing forward and the inner two-fifths 

 backward, but it enters the ventral surface of the stomach at 

 the same place, close to the anterior end (fig, 71). The digestive 

 tube is widened considerably in the head, then is narrowed through 

 the thorax and is abruptly contracted in the abdomen. The length 

 of the widened or stomach portion varies greatly in different genera. 

 In Lemanthro'pus and DichelesthiuTn the enlarged portion runs 

 through the entire body, remaining about the same diameter, and 

 is abruptly narrowed to the rectum on entering the abdomen. In 

 Hatschekia^ Eudactylina^ and Lamproglena the widened portion 

 begins to narrow somewhere in the thorax, and from there tapers 

 gi-adually to the anus. There is no definite place where it can be 

 said that one part ends and another begins. In Nemesis the intestine 

 retains its wide diameter through the fourth thorax segment and 

 is then rather abruptly narrowed in the fifth segment, after which 

 it tapers gradually to the anus without any definite rectum. In 

 Congerlcola., Kr0yeria, and Cyhicola the stomach narrows into 

 the intestine at the posterior margin of the head, remains narrow 

 through the free thorax segments, and then widens again in the 

 fused posterior body. The walls of the digestive tube contain both 

 longitudinal and transverse muscles, and by their rhythmic con- 

 traction and relaxation peristaltic movements run backwards and 

 forwards over the entire canal. By this means the canal contents 

 are pushed back and forth, a portion being thoroughly digested while 

 the rest is excreted. 



The epithelium in the esophagus and rectum is thin, and is made 

 up of smaller cells nearly uniform in size. In the enlarged portions 

 the epithelium is considerably thicker, and, especially in the anterior 

 stomach, contains many digestive cells, which are much larger than 

 the rest of the epithelial cells (fig. 68). 



Female reproductive system. — In the females of some genera like 

 Eatschehia^ Lemanthropus.^ Peniculisa^ Eudactylina^ Pseudocycnus^ 

 etc., the ovaries are situated in the anterior thorax or the anterior part 

 of the fused posterior body. In other genera like Nemesis., Dicheles- 

 thiu7n, etc., the ovaries are in the posterior part of the head, directly 

 above the stomach. The oviducts lead from the anterior ends of the 

 ovaries outward, downward, and backward, and are convoluted to 



