HOM(EOSOLEN. 
71 
Distribution. 
Bkitish : 
Cenomanian — Zone of Fecten aaper and zone of Schloenbachia t'ostrafa : 
Haldon Hills, Devon. 
Foreign : ^ 
Cenomanian: Essen, Germany ; Le Mans. 
Lower Planer : Plauen. 
Affinities. 
This species has been confused with its ally Homoeosolen tetragonus 
(Mich.), which is here, however, accepted as distinct. S. tetragonus 
differs by having thinner stems and more regularly reflexed 
branchlets ; the latter character is the less reliable, but the difference 
between the long, regular, dichotomous stems of H. tetragonus and 
the wide, flat, irregular branches of S. pinnatus seems to be of 
specific value. The sub-branches are often reduced to mere lateral 
processes. Simonowitsch has suggested that the difference between 
H. tetragonus and II. pinnatus may be only varietal. The Idmonea 
aculeata of Michelin seems to me clearly the same species as 
H. pinnatus, a conclusion adopted by von Hagenow in 1816. 
The section figured by Simonowitsch in 1871 ^ shows that the 
zocecia are monomorpliic. 
D’Orbigny has adopted the view that Michelin’s /. pinnata is 
a distinct species from that of Edmer, but as he lays stress on the 
great width of Eomer’s species it seems to me that Michelin was 
correct in his determination. 
LIST OF SPECIMEN'S. 
British. 
D. 7446. A zoarium in chert. Cenomanian — zone of Ptcten asper. Haldon Hills, 
south-west of Exeter. W . Vicary Coll. Bequeathed 1903. 
D. 7443. A large branched zoarium. Cenomanian — zone of Fecten asper. 
Haldon Hills, south-Avest of Exeter. W. Vicary Coll. Be- 
queathed 1903. 
D. 7445. A zoarium in chert. Cenomanian — zone of Ftcten asper. Haldon 
Hills, south-west of Exeter. W. Vicary Coll. Bequeathed 1903. 
D. 7444. A zoarium in chert. Cenomanian — zone of Fecten asper. Haldon 
Hills, south-west of Exeter. W. Vicary Coll. Bequeathed 1903. 
^ The species has been recorded from the French Senonian. 
2 Simonowitsch. Bry. Ess. : Verb. nat. Ver. preuss. Bheinl. vol. xxviii. 
pi. iv. hg. 1/. 
