10 H. F. NIEESTRASZ. 



ones, considering in tte first place the exact structure of the radula and salivary 

 glands. I propose the following division : — 



FAMILY PRONEOMENIIDAE. 



Index — at least — 6. Cuticle thick, with many layers of spicules, by far the greater part of which is 

 pointed and hollow. Epidermal papillae present. One or more dorso-terminal sense-organs. Radula and 

 salivary glands present. Gills are wanting. 



A. Radula multiserial. Salivary glands tube- or bag-shaped. 



Proneomenia Hubrecht. 



a. Radula with basal membrane. Salivary glands tube-shaped, uniting before opening 



out into the digestive tract. Receptacula seminis strongly folded, glandular. The 

 spicules remain connected with the epidermis by multinuclear stems. Abdominal 

 spicules present. Index 9-14. 



Proneomenia sluiteri Hubr. (4.) 

 (= langi Heuscher), 



Barent's Sea, Spitzbergen. 

 70-160 fathoms. 



b. Radula with basal membrane. Salivary glands tube-shaped, opening out separately. 



Receptacula seminis vesicular or tube-shaped. 



a. With abdominal 'and cloacal spicules. Receptacula seminis vesicular. 

 One dorso-terminal sense-organ. Index 22-50. 



Proneomenia weieri Nierstr. (6, p. 2.) 



East-Indian Archipelago, 22-1633 M. 

 Proneomenia longa Nierstr. (6, p. 7.) 



Saleyer, Bast Indian Archipelago, 1158 M. 

 p. Without abdominal, with cloacal spicules. Receptacula seminis vesicular. 

 Two dorso-terminal sense-organs. Index 10. 



Proneomenia discoveryi Nierstr. 



77° 50' 30" S., 165° 40' 5".E. 100 fathoms. 

 y. Without abdominal or cloacal spicules. One dorso-terminal sense-organ. 

 Receptacula seminis vesicular or tube-shaped. Index 9-18 '5. 

 Proneomenia valdiviae Thiele (16.) 

 3°7'S., 40°45'8"E.' 748 M. 

 Proneomenia acuminata Wiren (18, p. 68.) 



West India. 300 fathoms. 

 Proneomenia hawaiensis Heath (1.) 

 (? insufficiently known.) 

 Hawaian Islands. 

 Proneomenia fferlachei ¥el8. (10, p. 16.) 

 70° S., 80° 48' W. 500 M. 



c. Radula without basal membrane. Salivary glands tube- or bag-shaped, opening out 



separately. Receptacula seminis vesicular. 

 a. With abdominal and cloacal spicules. Salivary glands tube-shaped. 

 1-3 dorso-terminal sense-organs. Index 6. 



Proneomenia vagans Kow. a. Mar. (5, p. 29.) 

 Mediterranean. 

 j8. With abdominal, without cloacal spicules. Salivary glands bag-shaped. 

 Receptacula seminis numerous, often lobate. One dorso-terminal sense- 

 organ. Index 11. 



Proneomenia thulensis Thiele (14.) 

 80° 8' N., 16° 55' E. 480 M. 



