32 DEVONIAN FAUNA. 



Size. — 30 mm. long ; 5 mm. wide. 



Locality. — One specimen from tlie Marwood Beds of Baggy Point is in the 

 Barnstaple Museum. 



Remarks. — The only specimen known to me from the Pilton beds is too poor and 

 doubtful to be worth figuring. Its septa are very unequal, and are often more than 

 half the diameter of the shell in height ; though on the whole they seem rather 

 narrower than is usual in Sowerby and Phillips's figures. Phillips compares it with 

 0. regulao'e, Miinster,^ to which it is rather similar in some respects. 



It is recorded by Phillips from the Carboniferous localities of Venn and 

 Swimbridge, as well as doubtfully from Baggy Point. 



Affinities. — From 0. speciosum it difi'ers by its very much broader and more 

 unequal chambers. 



5. Orthoceeas, sp. Plate IV, fig. 6. 



Description. — Shell small, straight, tapering at the rate of 1 in 7. Septa 

 slightly oblique. Chambers about one quarter the width of the shell in height. 

 Siphuncle (or endosiphon ?) beaded, being constricted just below the septa into 

 narrow necks about half its width, and then swelling out into convex- 

 shouldered, straight-sided beads which are rather wider above than below, 

 have rather stout walls and a microscopically rugose surface, and are clothed 

 with a subsidiary envelope (or exterior siphuncle ?). Subsidiary envelope dumb- 

 bell-shaped, being very wide above and suddenly narrowing at about one-quarter 

 its length below the septa, its sides then becoming straight and then sometimes (?) 

 slightly expanding just above the next septum. 



Size. — A defective specimen is 30 mm. high by 8 mm. wide. 



Locality. — A single specimen from Kingdon's, Shirwell, is in the Barnstaple 

 Athenaeum. 



Bemarks. — This specimen only showing the section of the shell, it is almost 

 impossible to identify it specifically. It seems, however, to be distinguished from 

 accompanying species by the diS'erent height of its chambers, so that it probably 

 represents a distinct species. 



It seems remarkable for the arrangement of its siphuncular apparatus, which 

 in superficial shape exactly resembles that of Huronia. It is seen, however, that 

 the external envelope is entirely filled with white calcareous spar, and instead of a 

 linear endosiphon with expanding tubuli it contains a simple and entire beaded 

 tube. This tube Mr. Crick, who has very carefully examined the specimen with 

 me, regards as the true siphuncle. This being so, the exterior envelope, though 

 ' 1840, Miinster, ' Beitr.,' pt. 3, p. 95, pi. xvii, fig. 4. 



