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HEMICELLAEIA. 
HEMICELLARIA, d’Orbigny, 1850. 
[Prod. Pal. vol. ii. p. 86.] 
Synonyms. 
SemiceUaria, d’Orbif^y, 1853. 
Later oca red, d’Orbifrny, 1853. 
Iteteporidea, pars, d’Orbipiy, 1853 [non 1849). 
Diagnosis. 
Horneridsc with the transverse series of apertures sometimes- 
confused and irregular. The walls of the zooeeia are pittc'd 
by deep and numei'ous macuhr. The reverse is marked by 
interzooDcial depressions, or is cloaked by epitheca. 
Type Species. 
Hemicellaria ramosa, d’Orbigny, 1850. Prod. Pal. vol. ii. p. 80. 
Sornera lyerrieri, Pergens, 1890. Pevision, p. 353. 
The spelling of the generic name was corrected by d’Orbigny in 
1853 to Semicellaria but as Hemicellaria is equally correct and 
has three years’ priority, that name is accepted. The inclusion 
of H. ramosa and of d’Orbigny’ s Reteporidea ramosa in the same- 
genus rendered it necessary to rename one of them. Pergens 
changed the name of the fonner, though it was the older 
established species. 
Affinities. 
It is necessary to include in Hemicellaria some species referred to 
Laterocavea and Reteporidea. The former was founded by d’Orbigny' 
for two species, L. dutemplei, d’Orb., and L. punctata, d’Orb. : 
both of them were included by' Pergens in Idmonea, but it is 
necessaiy to exclude them from that genus OM'ing to the develop- 
ment of the epitheca and maculae. Reteporidea was founded in 
1849 by d’Orbigny, who made R. lichenoides, Goldf., his type species. 
That species is now included in Retecava, so that Reteporidea must 
be regarded as either a sy'nonymi of that genus or else replace it. 
But Reteporidea was so badly diagnosed that it is more convenient 
to accept Retecava, in spite of the fact that it was founded five 
years later. This course seems especially advisable, since d’Orbigny 
changed the use of the name Reteporidea', for in his “Cretaceous 
Bryozoa” he includes the type species in Crisina, and applies 
