118 THE NAUTILUS. 



rowly perforated Patulce, having no especial relations to Acanthimda. 

 The jaw and dentition of ^4. 7*'a?i»m Strebel are like the thin-shelled 

 ^Mexican Patulas, not at all like Acanthimda. The subgenus Tri- 

 chodiscina Martens {^^Trichodiscus Strebel, preoc.) includes the 

 forms grouping around H. coactdlata Fer. The very peculiar 

 species H. viacneili Crosse is included with doubt. If it really 

 belongs here, the name Averellia Ancey, 1887 (type H. macneUi) 

 will take precedence over TricJiodiscina. In 1889 the writer from 

 a study of specimens collected by Gabb, referred this species to 

 Cejjolis, although not without doubt. 



(Jo be coHiinued.) 



NOTES AND NOTICES. 



ZoNiTES Stekkii Dall. — I collected this species last Spring near 

 ]\[t. Lebanon, La., under damp leaves. Dr. Sterki kindly deter- 

 mined the specimens for me. — T. Wayland Vaughan. 



Notes on the Unionid^e of Florida and the Southeastern 

 States, by Charles T. Simpson, Aid in the Dept. of Mollusks, U. 

 S. National Mus. (32 pp., 26 pi. extract from Proc. U. S. Nat. 

 Mas. XV). In this critical study of the mussels of the southeast 

 drainage we find much to commend. Mr. Simpson discusses their 

 distribution, dividing our area into two regions, one the Mississippi 

 Valley with the Texas and eastern Mexican area as a subregion, the 

 other region comprising the States bordering on the Gulf of Mexico 

 from the Mississippi to Florida, and the Atlantic drainage north to 

 Canada, and also including the St, Lawrence (Great Lake) drain- 

 age. In this second region, the specific forms are comparatively few 

 and much less diversified in character than in the Mississippi drain- 

 age. One of the most ubiquitous types is Unio complanati(--<, which 

 extends, with variations, throughout the system. 



Lea's well-known classification of Unio is criticised and designated 

 as " artifical and not in accordance with all the facts of nature; " 

 and in this conclusion we heartily join Mr. Simpson. The arrange- 

 ment of Lea was a temporary expedient only, and bears about the 

 same relation to a natural system that the arbitrary systematic 

 botany of Linnteus bears to the modern natural system of plants. 

 The species are classified into "groups" by Mr. Simpson; and 

 under each one are given the synonyms, as he understands them, 

 with notes on distribution, and the salient specific characters of each 

 are pointed out. These notes, with the characteristic and generally 



