MUSEUM OF COMPARATIVE ZOOLOGY. 27 



antiquissima Eichwald, sp. McCoy, Annals Nat. Hist., VIII, p. 388, 1851. 

 The value of this section is doubtful. 



Subgenus Cranopsis Dall. Attached; upper valve with two. pointed slender 

 apophyses divaricating from the internal apex, where the muscular im- 

 pressions of the anterior pair are situated in the typical Cranice. Type 

 Crania Parisiensis, Defrance, Davidson, Me'm. Soc. Lin. Norm., X, pi. 

 xiii, fig. 23 a, b, 1856. 



Genus Craniscus Dall. Fixed valve divided by a transverse and a longitudi- 

 nal septum into three cells, the posterior of which contains the muscular 

 impressions and the rostrellum. Type Crania tripartita Munster, sp. 

 Davidson, 1. c fig. 21. 



It is extraordinary that the two sections here indicated have not been 

 separated previously, and indicates that this group has received little 

 attention from modern authors. The differences between the genera 

 Crania and Craniscus are hilly as great as any existing between the 

 acknowledged genera of the Terebralulidce ; and the characters of Cra- 

 nopsis, as separated from Crania, are well marked. The genus Spondylo- 

 bolus of McCoy appears to have rather more affinity with the Lingulidoz 

 than with this group, as I have elsewhere observed, and it is not in- 

 cluded here for that reason. 



The genus Pholidops Hall appears congeneric with PseudocraniaM.cCoy. 

 It is known principally from casts, however, and further researches may 

 establish its validity. 



Genus CRANIA Retz. 



Non binomial syn. Ostracitrs minimus . . . numulus Braltensburgcnsis diclus Sto- 

 b^eus, Act. Lit. Sci. Svec, pp. 14 and 21, 1731 * (fide Retz.), and Opuscl. 

 I, p. 31, Tab. l.figs. 1-3, 1752. 



Helmintholithus craniolaris Linne, Syst. Nat., XII, III, p. 162, 1768. 



Anomilcs craniolaris Drattensburgenscs et Ignaburgensis Wahlenberg, Act. 

 Upsala, 1821 * (fide Bronn). 



Nummuli Drattenburgencs Waller, Syst. Min., II, p. 500, 1775. 



Criopus Jimbriatus + Criopoderma (turbinatum) [taken collectively^ pars, Poli, 

 Test, utriusq. Sicil., I, p. 34, 1791 ; II, pp. 189, 255, 261, 1795 (fide G. 

 W. Tryon, Jr. 



Ostracites ?7iinimus, &c. Beuth, Jul. et Mont, subt, p. 130, 1776. 

 Actual syn. = Crania Retzius, Schrift., Berl. Ges. Naturf. Freunde, Bd. II, p. 

 72, 1781. — Philippson (?), Diss. Hist. Nat., p. 11, § v, No. 1, 1788.— 

 Schroter, Lith. Lex., IV, p. 265, 1785. — Bruguiere, Enc. Me'th. Vers., 

 I, tabl. p. xiii, 1789. — Defrance, Diet. Sci. Nat., XI, p. 312, 1818.— G. B. 

 Sowerby, Gen. Shells, fasc. XII, n. d., 1821 (?). Trans. Lin. Soc, XIII, 

 p. 431, 1822. — Hceninciiaus, Isis, p. 108, 1822* (fide Engelman).— 

 Nilsson, Kong. Vet. Ak. Handl., p. 378, 1824. Act. Holm., p. 326, 1825* 



