82 Reviews — B. B. WoodivardJs Life of the Mollusca. 



more species of freshwater mussels {Unio), of the thorny oyster 

 (Spondylidse), and cockles (Cardiidas). The oldest examples of the 

 ten-armed cuttlefish here made their first appearance. 



"The Jurassic strata are rich in molluscan remains, which some- 

 times form whole masses of rock. The Gastropods attained their acme 

 of development at this period. Further land shells and the earliest 

 freshwater Grastropods {Planorbts, Valvata, and Melania) have been 

 recorded from the lowest Jurassic beds, but of their exact determination 

 there is some doubt. In the uppermost beds, however, the well-known 

 Purbeck Marble is composed of masses of Valvata, Vivipara, etc." (p. 48.) 



" Among Bivalves genuine Ark Shells {Area), Anomia, and various 

 families of Eulamellibranchs, including the freshwater Cyrenidse, 

 made their appearance ; while if Corhtrella be admitted as a member 

 of the Septibranchia, that order must be added for the first time. 

 The ' pens ' and ink-sacs of earlier members of the Sepia tribe 

 {Beloteuthis and Geoteidhis) are first found in the Lias, with the 

 remarkable Belemnites whose ' guards ', often called ' thunderbolts ', 

 are familiar fossils. 



"In the succeeding Cretaceous period further development took 

 place. Among the Gastropods there was a decided increase in the 

 higher Pectinibranchs, including representatives of most of the 

 families of Rhachiglossa. Amongst Bivalves two most remarkable 

 aberrant families (Eadiolitidse and Hippuritidse) were confined 

 exclusively to this period. Externally these look not unlike simple 

 corals with a lid, while internally they display highly peculiar 

 modifications. Numerous other Eulamellibranchs, including some 

 boring forms such as Petricolidse and Saxicavidae, as well as the 

 Razor-fish [Ensis), arose, with an undoubted representative of the 

 Septibranchs {Leiopistha). An Octopus {FalcBoctopus Neivholdi') 

 standing for the highest Cephalopods was revealed for the first time 

 in the Cretaceous of Mount Lebanon, but, on the other hand, the 

 Ammonites and Belemnites died out. 



"During the Tertiary epoch the Rhachiglossa and Toxoglossa became 

 the dominant Gastropods, while the Bivalves showed an approximation 

 to present conditions. A great majority of the Lower Tertiary 

 (Eocene and Oligocene) genera still exist, but none of the species. 

 During the succeeding Miocene a few species, which are still in 

 existence, made their appearance, while of the Pliocene species 80 or 

 90 per cent, are represented in the recent fauna. 



"At the close of the Eocene the wide distribution of many types 

 now characteristic of warm, temperate, or tropical waters, began to 

 be restricted, and during the Miocene the faunal boundaries of the 

 Mollusca were mapped out nearly on existing lines. This was more 

 true of the non-marine forms ; but not till the Pliocene did each 

 geographical province come to assume its present distinctive 

 features." (p. 50.) 



Space does not admit of a more extended notice of this interesting 

 volume, which gives us in a few concise pages an accurate summary 

 of living and extinct Mollusca. There is an excellent index, 

 but we would suggest in the next edition a glossary for the 

 unlearned reader's use. A diagram of a Gastropod and a Pelecypod 



