124 Pi'of. Dr. M. Braun: Ber. üb. die wissensch. Leistungen 



III. Aberrante Formen. 

 A. Myzostomida (1884—1887). 



Das wichtigste Werk, welches uns eine grosse Zahl 

 neuer Formen kennen lehrt, ist die Bearbeitung des Ma- 

 teriales der Challenger-Expedition durch L. v. Graff; der- 

 selbe definirt die Myzostomida wie folgt: 



Ordo : Myzostomida „symmetrica! non-segmented animals, pro- 

 vided with an external chitinous cuticle, five pairs of movable para- 

 podia, each with a hook and supporting rod, an alimentary canal 

 with oral anal apertures ; through which latter the eggs are extruded. 

 Dioecious or hermaphrodite ; central nervous System consisting of 

 an oblong mass situated beneath the intestine, and giving off two 

 branches in front which encircle the pharynx, but bear no ganglia 

 and several othe pairs of lateral nerves, ]No circulatory, respiratory, 

 nor excretory organs. Parasitic on and in Crinoids. 



Farn. I. Stelechopidae : Myzostomida with straight alimentary 

 canal, parapodia independent of each other; no internal muscular 

 septa. Suckers obsent, Probably hermaphrodite, sexual products rea- 

 ching the exterior through a cloaca. 



Stelechopus n. gen.: the body is flat and long, the mouth at 

 the anterior margin, the cloaca at the posterior; alimentary canal 

 with no ramified coeca. Five parapodia on each side on the margin 

 of the ventral surface, each on of which contains a fine long hook 

 and a suppporting seta. The parapodia are entirely indepedent of 

 each other, the parapodial muscles being very simple, and the radial 

 musculi centrales, connected in the Genus Myzostoma with a central 

 muscular mass, are here absent. Instead of the radial muscular 

 bundles (septa) there are numerous parallel muscular bundles joining 

 the intestine to the body-wall. Suckers are wanting. — Mit St. 

 Hyocrini n. sp. auf Hyocrinus u. Bathycrinus von den Crozet-Inseln. 



Fam. IL Myzostomidae : Myzostomida with ramified alimen- 

 tary canal, parapodia connected by muscles which converge to a 

 central muscular mass. Body cavity divided into paired Chambers 

 by incomplete septa. Usually four pairs of suckers. Hermaphrodite 

 or dioecious. Ova evacuated through a cloaca, male generative aper- 

 tures situated laterally". 



Mit folgenden neuen Arten: 

 M. horologium von Actinometra jukesi Ph. H. Carp. und Actino- 



metara striata Carp., bei Cape York. 

 M. longipes, Wirth unbekannt, bei St. Vincent gesammelt von der 



Blake -Expedition. 

 M. chinesicum, Wirth unbekanut, aus dem chines. Meere. 



