25fi 



SCIENCE 



[N. S. Vol. XXXVII. No. 946 



hence the progress through families and gen- 

 era has been much slower. On the other hand, 

 considering the character of the work and the 

 numerous illustrations, we may well marvel at 

 the size of the yearly volumes, representing 

 an amount of labor which few of us could 

 undertake, even if possessing the necessary 

 skill. 



Professor Alpheus Hyatt died in 1902, leav- 

 ing a quantity of unpublished manuscript on 

 the Achatinellidse, those remarkably varied 

 and interesting snails of the Hawaiian Is- 

 lands. Some years later these materials were 

 turned over to Professor Pilsbry to be incor- 

 porated in the Achatinellidse of the " Manual." 

 The finished work is accordingly issued under 

 the names of Hyatt and Pilsbry, although 

 the greater part is by the junior author. The 

 large genus Leptachatina (92 pp.) is by Mr. 

 C. M. Cooke, of the Bishop Museum, Hono- 

 lulu. The Achatinellidse consist of two sub- 

 families, the arboreal Achatinellinae, with 

 usually light or brightly colored shells, and 

 the mainly terrestrial Amastrinaj. The whole 

 family is confined to the Hawaiian Islands, 

 excepting the genus Fernandezia from the is- 

 land of Juan Fernandez, which is located in 

 the group provisionally, in the absence of any 

 knowledge of the soft anatomy. The volume 

 under review contains only the Amastrinse; 

 before the Achatinellinffi are described Dr. 

 Pilsbry will himself visit the islands, and 

 gain a first-hand knowledge of the subject. 



The exhaustive and logical treatment, with 

 the fine colored plates, enables us to gain a very 

 good idea of the evolution and development of 

 the Amastrinse. The subfamily is to be di- 

 vided into two very distinct tribes, which if 

 given special names would be Leptachatinini 

 and Amastrini. The first of these consists of 

 oviparous forms, with shells closely resem- 

 bling those of the circumpolar genus Gochli- 

 copa. The second is to be divided into two 

 series, both viviparous, but one elongate or 

 Bulimoid, the other flattened or Helieoid. 

 The flattened shells (three genera) were orig- 

 inally, when known, regarded as species of 

 Helix, and the fact that they are indisputably 

 Achatinellid shows how difficult it is to cor- 



rectly place fossil land snails, knovm from the 

 shells alone. One of the Helix-like genera was 

 first (Ancey, 1889) named Tropidoptera, but 

 was renamed Pterodiscus by Pilsbry on the 

 ground that Tropidoptera was a homonym of 

 the earlier Coleopterous Tropidopterus. In 

 my opinion, Tropidoptera is a valid name,' 

 the difference in the ending sufficing to pre- 

 vent homonymy. I have long been familiar 

 with the genera Ancylus (Mollusca) and 

 Ancyla (Hymenoptera), and although using 

 both names, have never found the slightest 

 confusion to occur in my mind 



The number of new Amastrine species de- 

 scribed is large, indicating that the previous 

 work on the Hawaiian mollusca, although 

 voluminous, did not nearly exhaust the sub- 

 ject. The parts of the work most interesting 

 to the general zoologist are the introductory 

 chapter by Dr. Pilsbry, and the appendix 

 compiled from Hyatt's manuscripts. Accord- 

 ing to Professor Hyatt the animals migrated 

 from island to island in ancient times, and in 

 some cases he even indicates the probable 

 landing places of the immigrants and their 

 subsequent migrations. Dr. Pilsbry, while 

 fully agreeing with many of Hyatt's views, 

 especially those on taxonomy, holds that while 

 the snails did indeed migrate in various ways, 

 it was on dry land. That is to say, the 

 Hawaiian Archipelago was once a single large 

 island, which presently divided into two, later 

 into four, and finally reached its present con- 

 dition. Good arguments are given in support 

 of this hypothesis, and one can not help feel- 

 ing that they would have convinced Professor 

 Hyatt, had he lived to consider them and to 

 go over all the evidence available at the pres- 

 ent time. It is impossible in a review to ade- 

 quately discuss this matter, but it is very evi- 

 dent that the whole subject is of the greatest 

 interest to students of evolution, and when 

 worked out from every point of view, may give 

 us a definite idea of the time required for the 

 evolution of species of various groups in the 

 Hawaiian Islands. It is supposed that the 

 large island Hawaii had only its most north- 



" It is well to note that it has been omitted from 

 the "Index Zoologicus. " 



