NO. 6 ANNELIDA, ONYCHOPHORA, AND ARTHROPODA SNODGRASS 65 



most part are not closely grouped into bundles forming specific 

 muscles as in the arthropods. Each fiber is invested in a delicate 

 sarcolemma, the nuclei are superficial, and the axis is distinctly fibril- 

 lated but shows no trace of cross striatio.n (see Camerano, 1897). 



The following account of the onychophoran body musculature is 

 based on a study of Peripatoides novae-zealandiae . When the body 

 is laid open from above there are exposed on each side three sets of 



DV dm 



SlmGld 



/ 



siGia 



Fig. 29. — Cross-section of middle body region of Peripatoides novae-zealandiae 

 Hutton, showing position of principal organs, diagrammatic. 



AlCnl, alimentary canal ; Com, commissure of nerve cords ; DDph, dorsal 

 diaphragm; dm, dorsal muscles; DS, dorsal sinus; DV, dorsal blood vessel; 

 dmn, dorsoventral lateral muscles; 113C, lateral compartment of body cavity; 

 mBC, median compartment of body cavity; NC, nerve cord; Nph, nephridium; 

 Npr, nephropore, SlGld, salivary gland; SlmGld, slime gland (reservoir); 

 zmi, ventral muscles. 



fibers. Dorsally is a broad, thin band of internal dorsal longitudinal 

 fibers (fig. 30, /), the more median fibers beginning anteriorly at the 

 bases of the antennae, the more lateral ones behind the bases of the 

 oral papillae. Ventrally is a much narrower band of ventral longi- 

 tudinal fibers {2) lying along the midventral line. Between the dorsal 

 and ventral longitudinal muscles is a series of fiat, closely adjacent, 

 straplike lateral dorsoventral muscles (fig. 29, dvm, fig. 30, j), begin- 

 ning anteriorly midway between the oral papillae and the first legs. 

 When fully exposed, however, these lateral muscles are seen to be 



