62 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
size of the transverse diameter, arising mostly from the size of the initial or 
embryonal segment, that create a lot of variations. 
Pacific. 978, 1740 fathoms; scarce and starved. 
Caribbean Sea. 100-400 fathoms ; not scarce (Goös). 
ALLIED Form :— 
N. Boueana D'Or». Plate VI. Fig. 2. 
Dental. Boueana p'ORR., 1846, Dass. tert. Vienne, p. 47, Pl. II. Figs. 4-6. 
Nodos. communis var. Goiis, 1882, Ret. Rhizop. Caribb. Sea, Sv. Vet. Ak. Hdl., 
XIX. 4, Pi. 1. Figs. 18, 14, 15. 
Nodos. filiformis BR., 1884 (partly), Chall. Rep., IX. p. 500, Pl. LXIII. Fig. 3. 
Nodos. Boueana Goks, 1894, Sv. Vet. Ak. Hdl., XXV. 9, p. 69, Pl. XII. Fig. 689. 
A very attenuated form, with long and narrow elliptic or cylindric seg- 
ments and more or less constricted sutures. Nodos. ovicula D'ORB. is to 
be considered as a riper form of Boucana. 
From Dental. filiformis D’ORB. it is faintly distinct, by its longer and 
not globular segments. But it very often happens that the young stage of 
Boucana is provided with quite globular segments, and the mature part 
of the same colony with long-ovoid ones, 2-3 times longer than broad. 
From Orthoceras farcimen (= Dentalina communis D'ORB., 1826) it is 
hardly distinguishable, although that form should have somewhat shorter 
and wider segments. 
Caribbean Sea, 65-200 fathoms. 
N. soluta Revss. 
Dental. soluta Reuss, 1851, Septar. Thon Berlin, Ztschr. deut. geol. Gesellsch., III. 
p. 60, Pl. III. Fig. 4 (nearly identical with pyrula n'Onn.). 
Dental. soluta Reuss, 1866, Deutsch. Septarienth., Wien. Ak. Dkschr., XXV. p. 
131, Pl. II. Figs. 4-8. 
N. soluta BR., 1884, Chall. Rep., IX. p. 503, Pl. LXII. Figs. 13-16. 
N. soluta Goiis, 1894, Arct. & Scand. Foramf., Sv. Vet. Ak. Hdl., XXV. 9, p. 70, Pl. 
XII. Fig. 690. 
This form is sometimes hardly distinguished from N, pauperata, of which it 
may be a megalaspherie offspring on one side, and from N. pyrula on the other. 
Some of the specimens designed by Reuss as soluta seem to be very close to 
pyrula by having some traces of segmental necks, 
Pacifie. 995-1201 fathoms. 
Jaribbean Sea. 169-821 fathoms. 
N. monile Sorp. 
Nodos. radicula. var. monile Goñs, 1882, Ret. Rhizop. Caribbean Sea, Sv. Vet. Ak. 
Hdl., XIX. 4, p. 15, Pl. I. Figs. 3-6. 
Nod. pyrula Br., 1884, Chall. Rep., IX. p. 497, Pl. LXIT. Figs. 10-12, 
