1416 THE VOYAGE OF H.M.S. CHALLENGEE. 



4. Theocorys ovata, n. sp. (PL 69, fig. 16). 



Shell quite ovate, thick-walled, smooth, without external strictures. Length of the three joints 

 = 2:2:9, hreadth = 3:5:7. Cephalis conical, with a thick conical horn of the same length. 

 Thorax and ahdomen gradually dilated towards the base, and then hemispherical, constricted. 

 Mouth scarcely one-third as broad as the abdomen, prolonged into a short tube. Pores regular, 

 circular, disposed in transverse rows, two to three in the cephalis, two to three in the thorax, eight 

 to ten in the abdomen. 



Dimensions. — Length of the three joints, a 0-02, b 0-02, c 0-09 ; breadth, a 0-03, b 0-05, c 0-07. 



Habitat. — Central Pacific, Stations 263 to 268, depth 2650 to 3000 fathoms. 



5. Theocorys plutonis, n. sp. (PL 69, fig. 1). 



Shell ovate, thick-walled, smooth, with two slight strictures. Length of the three joints = 

 2 : 5 : 4, breadth=4 : 7: 6. Cephalis hemispherical, with a conical, oblique horn of the same 

 length. Thorax and abdomen only slightly inflated, gradually decreasing towards the wide, httle 

 constricted mouth. Pores subregular, circular, much larger in the abdomen and the lower half of 

 the thorax than in the upper half and the cephalis. 



Dimensions. — Length of the three joints, « 0-02, b 0-05, c 0-04 ; breadth, a 0-04, b 0'07, c 0-06. 



Habitat. — South Pacific, Station 295, depth 1500 fathoms. 



6. Theocorys scolopax, HaeckeL 



Euciirtidium scolopax, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 72, 

 Taf. ix. fig. 5. 



Shell slender, inversely ovate, smooth. Length of the three joints = 1:3:3, bi-eadth = 1 : 4 : 4. 

 Cephalis subspherical, with a long, slightly curved horn, half as long as the whole shell. Thorax 

 campanulate. Abdomen inversely ovate, twice as broad as the constricted mouth (incomplete in 

 Ehrenberg's figure). 



Dimensions. — Length of the three joints, a 0-02, b 0'06, c 0'06 ; breadth, a 0'02, b O'OS, c 0-08. 



Habitat.— ¥o?,&i\ in Barbados. 



Subgenus 2. Theocoryihium, HaeckeL 



Definition.- — Pores of the thorax and of the aLdomeu of difi"erent sizes or dissimilar 

 forms. 



7. Theocorys diance, n. sp. (PL 69, fig. U). 



Shell almost ovate, with two deep strictures. Length of the three joints = 3:6:8, breadth = 

 3:9:8. Cephalis subspherical, with a slender, pyramidal horn of three times the length. Thorax 



