GENUS ALVEOLINA: HISTORY AND ORGANIZATION. 553 



ceding, yet the two really bear a very close relationship in all essential points of 

 minute structure, as will appear from the particulars I shall presently have to detail. 

 The following outline of what has been previously ascertained respecting it (for 

 which I am indebted to M. D'ORBIGNY*), will show how little the nature of its 

 organization has hitherto been understood. Most of the species at present known 

 are fossils, occurring in association with Nummulites, Orbitolites, &c. in the Num- 

 mulitic limestone, or in other formations which represent it; and the examples first 

 described (by FORTIS) were confounded with Nummulites and Orbitolites under the 

 term Discolites. By FICHTEL and MOLL, they were ranked as a sub-type of their 

 comprehensive genus Nautilus. The designation Alveolites was first given to this type 

 by Bosc-f-; but it was not generally adopted ; and MONTFORT, according to his wont, 

 raised three of Bosc's species to the rank of genera, under the names of Borelia, 

 Clausalia, and Meliolites. LAMARCK did not adopt either Bosc's or MONTFORT'S 

 generic designations, but substituted a new one, Melonia ; and this was adopted by 

 CUVIER and FERUSSAC. DEFRANCE proposed yet another name, Orizaria. And 

 finally M. D'ORBIGNY, in 1825', adopted Bosc's name, with a slight alteration in its 

 termination, which served at the same time to mark the continued existence of the 

 type, and to distinguish it from a genus of Corals which also had received the name 

 of Alveolites. The name Alveolina was soon afterwards adopted by M. DESHAYES ; 

 and it may now be considered as the established designation of the genus. The 

 following is the latest definition given of this type by M. D'ORBIGNY : "Coquille 

 allongee dans le sens de 1'axe d'enroulement, formee de loges divise"es par des canaux 

 capillaires, ronds, perches de nombreuses ouvertures placees en lignes transversales a 

 1'enroulement spiral." Not the least idea seems to me to be conveyed by this defini- 

 tion of the real structure of these bodies, such as is brought into view by thin 

 sections; and no one, so far as I am aware, has previously attempted thus to eluci- 

 date it. 



93. Organization. My investigations have been made upon specimens which were 

 tolerably abundant both in Mr. JUKES'S Australian dredgings, and in Mr. CUMING'S 

 Philippine Collection. These were obviously identical specifically, but the latter con- 

 siderably exceeded the former in average size. The length of the longest complete 

 specimen in my possession is '35 of an inch; but I have a specimen whose shape is 

 somewhat abnormal indicating that it has increased with unusual rapidity in length, 

 as proportioned to its diameter, which, though incomplete at one end, measures '50 

 of an inch. The ordinary form, from which any considerable departure is very rare, 

 is that which is exhibited in Plate XXVIII. fig. 23 ; and it is obviously produced, as 

 correctly stated by M. D'ORBIGNY, by the involution of a spiral around an elongated 

 axis. The surface is marked-out by longitudinal furrows into a succession of bands 

 of tolerably uniform breadth ; and each of these is crossed by secondary furrows, 



* Foram. Foss. de Vienne, p. 140. 



t Bulletin des Seances de la Societe Philomathique, No. 61. 



