MUSEUM OF COMPARATIVE ZOOLOGY. 201 
Habitat. Stations 290, Barbados, 73 fms. ; 232, St. Vincent, 88 fms.; 155, 
Montserrat, 88 fms. ; 253, Grenada, 92 fms. ; 273, Barbados, coral and shells, 
103 fms. ; 45, in Lat. 25° 33’ N., and Lon. 84° 21’ W. Gr., 101 fms.; 177, 
Dominica, sand and shells, 118 fms. ; 157, Montserrat, sand and stones, 120 
fms. ; 297, Barbados, stones, 123 fms. ; 258 and 254, Grenada, 159 and 164 
fms. ; 193, Martinique, 169 fms. ; 291, Barbados, 200 fms. ; 139, Santa Cruz, 
sand and gravel, 218 fms. ; 147, St. Kitts, 250 fms. Its location, therefore, 
appears to be between seventy and two hundred and fifty fathoms, in water 
varying from 51°.0 to 699.0 Fahrenheit in temperature. 
The relations of this form appear to be with 7. vitrea, T. cubensis, T. sphe- 
noidea, and T. scille. Its assemblage of characters does not appear to be shared 
by any of those forms. The rather large number of specimens of all ages, col- 
lected as above, show its range of variation very well. Those who would unite 
all the above-mentioned species under one name, would doubtless include the 
present form within that limit, and logically so. I do not see my way clear, 
however, whatever may be thought to be the value of a “species,” to ignore 
what appear to be constant differences in the organisms under consideration. 
It is probable that there are too many specific names in the group of Terebra- 
tula of which T. vitrea is an example, a number of additions having been re- 
cently made to the list. The present form is certainly more differentiated 
from either vitrew or cubensis than several which have been named and are 
generally accepted. The form of the loop resembles closely that of T. siracu- 
sana Seguenza (Bull. Malac. Ital., IV., tab. 4, fig. 13), its general form is more 
like T. scille Seg. (1. c., tab. 3, fig. 8), at least like the variety mentioned. 
Other discriminating characters may be found mentioned in the preceding 
description, which, with the figures, will be a sufficient means for identification. 
The anterior flexuosity is often, though not usually, as strong relatively in the 
young as in the adult. The appressed neural apex is very constant. 
Terebratula incerta Davipson. 
Megerlia incerta Davidson, Challenger Brach., p. 49, pl. xi. figs. 17, 18, 1880. 
Plate VI. Figs. 6, 6 a. 
Habitat. Challenger Expedition, Mid-Atlantic, Lat. 1° 47’ N., Lon. 24° 26' 
W., 1850 fathoms. Blake Expedition, Stations 235 and 236, in 1507 and 1591 
fms., oozy bottom, off Bequia, bottom temperature 39°.0 F.; and Station 16, 
292 fms., off Morro Light, Havana, Cuba, bottom temperature 55°.6 F., one 
specimen only. 
This species was obtained of adult size at the stations cited. It is readily 
recognizable from Mr. Davidson’s excellent figures (by his kindness I com- 
pared specimens) and the peculiar and characteristic radiating filaments which 
surround the base of the peduncle. In all the specimens examined the loop is 
incomplete, or rather the crura are not united, but the soft parts, the sete, and 
