21 



gills never occur. These are only met with in a few forms, viz; in Fruvotia sopita, Macellomenia 

 palifera, Paramenia impexa and sierra, and Neomenia. From Pruvotia it is clearly distinct by the 

 possession of radula and salivary glands. From Paramenia impexa it greatly differs by the presence 

 of 2 salivary glands and of a monoserial radula. Stronger is the resemblance to Paramenia 

 sierra, where the dorsal salivarj- glands are absent. It considerably differs from Macellomenia 

 palifera with its mono.serial radula, the structure of the salivary glands and of the integument 

 being entirely different. 



Still in other respects e. g.. as regards the shape of the spicula, and the structure of the 

 cloaca-ducts and cloaca there is a difference between this form and Pruvot's Paramenia. Pruvot 

 gives the following characteristic for the genus Paramenia: a thick cuticle ("cuticula crassa", 4, 

 pag. 724). Regarding this the following must be noticed: the cuticle is not thick; for Paramenia 

 impexa Pruvot does not give a description of the cuticle, but as we can learn from his fig. 73, 

 the cuticle is anything but thick, whilst for Paramenia sierra he admits, that the cuticle is 

 rather thin (10, pag. 483). Simroth rightly mentions the thin cuticle as being characteristic 

 for the genus Paramenia (7, pag. 232). 



The Xeomeniidae may be arranged into 2 groups : 



i" Forms with thick cuticle, with numerous pointed, hollow spicula in different layers and 

 provided with a great number of hyjjodermal ])apillae. 



Neomenia Tullberg. 

 Proneomenia Hubrecht. 

 Rhopalomenia Simroth. 

 Pruvotia Thiele. 

 Strophomenia Pruvot. 

 Dinomenia nov. gen. 

 (?) Notomenia Thiele. 



2" P'orms with thin cuticle, covered with a layer of flat, imbricated spicula, without hypodermal 

 papillae. 



1 )ondersia Hubrecht. 

 Lepidomenia Kow. & Mar. 

 Ismenia Pruvot. 

 Myzomenia Simroth. 

 Macellomenia Simroth. 

 Nematomenia Simroth. 

 Stylomenia Pruvot. 

 P'chinomenia Kow. 



Paramenia (Pruvot) may be called intermediate between the two groups : Paramenia impexa 

 ajjproaches more closely group i. Paramenia sierra group 2. 



Proparamenia offers more points of comparison with the first group : the cuticle is 

 thick, the spicula, disposed in many layers, are of the Proneomenia-shape and the papillae are 

 numerous. For this reason as well as on account of the monoserial radula it seems to me 



