TEREBRATULA.—Puiate I. 
It is not convenient, nor indeed practicable, to give the 
descriptions and figures of shelis in this work in their na- 
tural order; but in the case of the present genus I have 
indicated the systematic distribution of the species now 
commonly adopted, by using the newly-introduced names 
of genera as sub-genera. ‘The variations of the apophysis 
upon which these are founded are as follows :— 
1. WaLpueimta, King ; a free, largely-produced ribbon- 
like loop, considerably reflected. Pl. 2. f. 3 a. 
Nine species. 
2. TerEBRATULA, Lhwyd; loop small, simple, not re- 
flected. Pl. 3.f. 8a. Two species. 
3. TEREBRATULINA, D’Orb. ; loop small, arched into a 
circle on projecting blades. Pl. 4. f. 15 ¢. Six 
species. 
4. TEREBRATELLA, D’Oré. ; a freely-produced ribbon- 
like loop, resembling that of Waldheimia, and si- 
milarly reflected, but strengthened across the mid- 
dle by the additional attachment of a cross pro- 
cess affixed to a central septum. Pl. 5. f. 20a. 
Eleven species. 
5. Maeas; loop resembling that of Terebratella but 
more contracted, with the cross process more 
broadly laminated next the septum. PI. 8. f. 31 a. 
Two species. 
6. Boucuarpta ; loop obsolete owing to the callous 
thickening of the hinge and adjacent parts; apo- 
physes represented by the septum and laminated 
processes of Magas produced and thickened into the 
form of an anchor. PI. 8. f. 33. Three species. 
. Kravssta; no loop; apophysis represented by a 
central septum, from the extremity of which di- 
verge a pair of fan-like processes. Pl. 9. f. 87a 
and 38 4. Five species. 
8. MrcEeRLE ; loop moderate, trebly attached, to 
blades projecting from the hinge, to a broad cross 
process affixed to a central septum, and on either 
side by a short intermediate lobed process. Pl. 11. 
f. 47 6. One species. 
9..GwynrIA?; apophysis unknown. One species. 
10. Morris1a ; loop short, attached to a central process 
in the form of a spur, not reflected. Pl. 10. f. 41. 
Three species. 
11, AraiopE ; loop lobed, sweeping round the valve, 
supported in front by one to three short marginal 
septa. Pl. 10. f.43a@ and 45a. Four species. 
12. TuEcIpDEA ; loop four-lobed, callously affixed to the 
valve. Pl. 11. f. 48 e. 
Geographical Distribution. 
~ 
One species. 
It is difficult to generalize on the geographical distri- 
bution of the Zerebratule, with the hope of arriving at 
many conclusions of interest, without embracing the fossil 
species. As might be expected in the case of a tribe of 
animals which existed so much more abundantly in the 
primeval seas, and are perhaps destined at no very remote 
period to disappear altogether, they are much scattered, 
and are not abundant in individuals. Nevertheless there 
are few genera of mollusks of which the habitats and spe- 
Of the forty-eight 
recorded species of Zerebratula (cited rather at random by 
authors at from sixty to seventy in number), four are based 
upon single specimens of somewhat doubtful specific value, 
without any information as to their habitats,—cancellata, 
Bouchardii, transversa, suffusa ; but their relationship with 
undoubted species is not sufficiently obvious to admit of 
their being discarded. Of three species (radiata, supposed 
to be a native of Corea; crenulata, of the Canaries, and 
dilatata, of Coquimbo, or the Strait of Magellan) the ha- 
bitats are not well authenticated, and appear to me to be 
doubtful. Of the habitats of the remaining forty-one spe- 
cies there is no manner of doubt; but of two of these the 
specific value is open to criticism—physema and capsula. 
There remain, then, thirty-nine species of which the sub- 
genus (founded on the structure of the apophysis), the 
species, and the habitat may be relied on. 
cific nature are now so well known. 
DISTRIBUTION OF SPECIES IN PROVINCEs. 
Eastern Hemisphere. 
Terebratulina abyssicola. 
Terebratella Coreanica. 
IV. Indo-Pacific Province. 
Waldheimia picta. 
Terebratulina Cumingii. 
Terebratella sanguinea. 
I. North European. 
Waldheimia cranium. 
septigera. 
Terebratulina caput-serpentis. 
Terebratella Labradorensis. 
Spitzbergensis. 
II. Lusttanian Province. 
Terebratula vitrea. 
V. Australo-Zealandic Province. 
Waldheimia flavescens. 
Terebratulina caput-serpentis. lenticularis. 
Megerlia truncata. Terebratella cruenta. 
Morrisia Anomioides. rubella. 
Dayidsoni. rubicunda. 
lunifera. Magas Valenciennesii. 
Argiope decollata. Bouchardia fibula. 
cuneata. Cumingii. 
—— Neapolitana. Kraussia Lamarckiana. 
— cistellula. 
Thecidea Mediterranea. 
Ill. North Asiatic Province. 
Waldheimia Grayi. 
Terebratulina Japonica. 
VI. South African Province. 
Kraussia rubra. 
cognata. 
—— pisun. 
—— Deshayesii. 
Western Hemisphere. 
VII. Magellanic Province. 
Terebratula uva. 
Terebratella Magellanica, 
VILL. Panamie Province. 
Terebratula uva. 
Waldheimia globosa. 
