40 FORAMINIFERA OF THE CRAG. 



Characters. — Shell ovato-globose or pear-shaped, usually Entosolenian. Surface 

 covered with an ornamentation of elevated ridges, forming* a network with hexagonal 

 or sub-hexagonal meshes. Colour white to yellowish. Length ^th or less to j'^th inch. 



This represents a state of ornamentation peculiar to \.\\q LagnncB amongst the "hyaline," 

 and to certain varieties of Miliola seminulmn among the " porcellanous" Foraminifera. 

 In L. Melo the cross-bars are often weaker than the longitudinal ribs, and pass straight 

 across from rib to rib, like the secondary veins in a monocotyledonous leaf, such as 

 Aiisma, Mjjrsip/i^Uum, &c. In L. squamosa, however, not only have the secondary riblets 

 become equal to the primary, but, by the zigzag inflection of the latter, a nearly regular 

 hexagonally areolated ornament is produced, reminding one strongly of the polygonal 

 meshes produced by the more perfect reticulation of the woody skeleton of a dicotyledonous 

 leaf. Early observers, using but imperfect microscopes, compared this retose ornament 

 with a scaly skin of a fish (see Williamson, 'Monograph,' p. 12), and, indeed, from young 

 and small specimens, mounted in Canada balsam and viewed as transparent objects, it 

 would be almost impossible, even with the best inslruraents, to contradict such a 

 diagnosis. 



Professor Reuss, in his ' Memoir on the Laffenidae,' pi. 5, fig. 74, figures, under the 

 name of L. yeometrica, a very beautiful modification of this variety, in which the ornament 

 takes the form of very small, regular, hexagonal meshes, separated by delicately thin 

 elevated walls. Professor Williamson's figure (' Monogr.,' pi. 1, fig. 32) of L. squamosa, 

 var. hexaffona, represents a similarly regular marking, but here the ridges are broader, 

 and the number of meshes finer. His L. squamosa, var. scalari/ormis, has the same 

 general character, but there is proportionately a smaller amount of ornament, and the 

 interstitial spaces are still larger. 



In this reticulate Lagena the neck is usually intussuscepted (Entosolenian) ; but in one 

 of the large fossil form {L. squamoso-tubifera, Parker and Jones, ' Phil. Trans.,' 18C5, pi. IS, 

 fig. 7), the neck is protruded in some cases to a considerable extent, and has about three 

 secondary tubuLir apertures arising fi'om it laterally, and almost at right angles to the main 

 tube. This is an isomorphism with Polfmorphina tuhulosa, and with certain feeble bifur- 

 cating forms of Nodosaria from Cretaceous beds. 



L. squamosa is of world-wide occurrence ; but, like L. Melo, is not so abundant as the 

 long flask-shaped and the marginated forms. In the Arctic Seas it is not uncommon, 

 and on our own shores it is found sparingly everywhere. It is found fossil in the Black 

 Crag of Antwerp (Reuss), and in the Tertiary clays of North Italy. By far the bulkiest 

 specimens of L. squamosa that we have seen are from a Tertiary sand, which, rich in many 

 varieties of Logenm, in Ovulites, Polt/morp/mm, and Vertebralina, was taken from the 

 inside of a Cerifhium giganteum from Grignon. A single specimen collected by Mr. H. C. 

 Sorby, at Bridlington, kindly placed in our hands with his other specimens from the 

 same locality, is the only instance we know of its occurrence in the Pliocene beds of 

 Britain. 



