lf.OtMM 



Fig. 56. Diplectanum aculeatum 



varies (Fig. 57) from simply arranged needle-shaped thorns to complex 

 thorns with numerous points on the free edge and with a massive basal part. 

 In a number of cases, these thorns are equipped with special musculature 

 and can move independently of each 

 other. In separate species the number 

 of rows of thorns fluctuates from a 

 significant number (more than 100) 

 to comparatively few (a little more 

 than 10) while among the species with 

 a smaller number of rows the shape 

 of the thorns is usually the most 

 complex. In addition to that, among 

 species with a small number of rows 

 of thorns, the edge of the body forms 

 symmetrical growths, and the thorns 

 are located in the middle of these 

 growths. The complex of the 

 growth with thorns, which is sup- 

 plied with a special musculature, 

 is very reminiscent of the para- 

 podia of higher worms and un- 

 doubtedly represents a primitive 

 formation which aids in locomotion; 



we called it a propodium (Fig. 58). The question concerning these propodia 

 and their development and morphology will be examined in detail in another 

 work. The musculature is very strongly developed among monogenetic tre- 

 matodes, particularly in the region of the attaching apparatus. It is rep- 

 resented by dermal parenchymatose fibers (concerning the musculature of 

 the sexual ducts and organs, see page 4 ). The dermal musculature typi- 

 cally consists of circular, diagonal 

 and longitudinal fibers. As a rule 

 the longitudinal musculature is the 

 most powerfully developed, often it 

 forms powerful longitudinal muscular 

 W1'2mm\ \ \ „ ^ \ y { \ ligatures (ligaments, nobis) which 



These 



Parona and Perugia, the posterior 

 end of the body of an adult v/orm from 

 the gills of Corvina nigra Cuv. and 

 Val. from the region of Karadaga 

 (Black Sea). 



Fig. 57. Skin thorns of various 

 shapes, Capsalidae. 



are isolated from each other, 

 ligatures which are mainly located on 

 the posterior end of the body, change 

 into muscles which serve for the move- 

 ment of the central elements of the attaching armamert and for common 

 coordinating movement of the entire attaching disc. According to Maclaren, 

 in Diplectanum aequans Wagener (Fig. 59) the longitudinal dermal muscula- 

 ture falls into two layers, exterior --lying directly under the circular layer, 

 and interior--lying under the diagonal layer. Similar relationships have a 

 certain similarity with the disposition of musculature of the dermomuscular 

 sac among Gyrocotyloidea and Cestoidea. There are indications which point 

 to the absence of the diagonal musculature among certain Hexabothriidae. 



44 



38 



