+ CATALOGUE OF PHANEROPNEUMONA. 
Cyclostomoidee, Agassiz, 1847, Vom. Zool. Ind. Univ. 
Cyclophoride, Gray, 1847, Proc. Zool. Soc. p.181; 1850, Catal. 
Cycloph. p.5; Pfeiffer Pnewm. 
The genus Cyclostoma of Lamarck was for a long time the only 
one constituting this family, till, by a more accurate knowledge 
of many new species, and of their very different opercula, it 
became necessary to separate from the original genus several 
distinct types, increasing gradually to the number of thirty 
genera (including a fossil one). 
In 1840, Dr. Gray (Synopsis, Brit. Mus. 133) formed the genus 
intoa family, Cyclostomide, and divides them into genera thus :— 
“Tn the Cyclostoma, which have a shell operculum, and simple 
mouth to the shell, the foot of the animal is divided into two 
equal parts by a longitudinal groove, and the animal walks by 
alternately moving forward first one and then the other of these 
sides. In Cyclophorus Pterocyclos, and Megalomastoma, which 
have a horny many-whorled operculum, the foot is simple, 
and the animal glides along like the other Gasteropodes. 
Some of these, as Pterocyclos, have a more or less developed 
groove or hole at the hinder angle of the mouth, evidently 
formed by some periodically-developed process of the edge of 
the mantle. In others, as dMegalomastoma, there is a permanent 
appendage to the mantle, which produces a groove and ridge in 
the front of the mouth near the pillar ; and in Pupina, which 
has been confounded with Buccina, the groove ends in a narrow- 
edged marginal notch. The Callie have a peculiar polished shell, 
very like the former, but they want the groove. The fossil genus, 
Strophostoma, is peculiar for the animal, when it is approaching 
to its adult state, suddenly reversing the position of its body, 
so that the mouth of the shell is placed on a plane with the 
surface of the spire, as in the genus Anostoma, among the 
Helices. The Pomatias have an elongated shell, with reflexed lips, 
and a horny oval operculum.” 
Then follows this list of genera, in which the specimens were 
arranged in the Museum collection :— 
A. 1, Cyclostoma ; 2, Licina; 3, Poteria; 4, Leonia. B. 5, Annu- 
laria; 6, Bolania; 7, Cyclotus; 8, Pterocyclos ; 9, Strophostoma. 
C. 10, Realia ; 11, Megalomastoma. D. 12, Callia. HE. 13, Pu- 
pina; 14, Registoma. F. 15, Pomatias. 
In 1840, Mr. Swainson (Malaccology, ii. 336) divided the genus 
Cyclostoma into four subgenera, with the following types :— 
1, Cyclophora, Montf. (C. volvula) ; 2, Cyclostoma, Cabio ; 3, Cyclo- 
tus, Guild (planorbulata) ; 4, Megalomastoma, Guild (flavula). 
In 1847, Dr. Troschel (Zeitsch. f. Malak. 44) proposed to divide 
the family into the following genera :— ; 
