288 General Notes. [March 
we supposed. We cannot perceive that it affects the evidence 
tending to show that it has been introduced.— W. F. Ganong. 
Development of Alpheus.—Mr. F. H. Herrick contributes to 
No. 54 of the Circulars of Johns Hopkins University an ac- 
count of his researches on the development of several species of 
the shrimp Alpheus. There is a small cup-shaped gastrula, and 
the early rudiments of the embryo have a V-shaped outline, the 
base of the V being formed by the rudimentary abdomen. The 
three nauplius appendages appear nearly simultaneously, and 
the upper lip grows out between the first and second antenne. 
The later history of the eyes is traced, but the optic invagination 
described by Reichenbach in Astacus and Kingsley in Crangon 
was not noticed. 
-Sea Isopoda.—In the 77 SP of the Zoological So- 
Se (vol. xii. pp. 77-141, pls. 16-27, 1886) the Rev. A. M. Nor 
man and the Rev. T. R. R. Stibbing enumerate and describe ihe 
deep-sea Isopoda of the families Apseudidæ, Tanaidæ, and An- 
thuridæ, which have been taken by the recent English ‘dredging 
expeditions in the “ Lightning,” “ Valorous,” and “ Porcupine.” 
In all, twenty-six species are enumerated, of which seventeen are 
new. Several new genera are characterized: Sphyrapus, a 
nella, Alaotanais, Cyathura, Anthelura, Hyssura, and Calathur. 
nea Harger and A. polita Stm. are referred to Cyathura carinata 
(Kr.). Anthura fraiata Stm. is made the of the new 
genus Calathura. Under the general account of the family Ta- 
naidæ are some very interesting remarks on the existence of 
two forms of males in this group: 
«anatomy of the genus Pliodon, which throws light on the rela- 
tionship of this mollusc, the affinities of which were uncertain 
before. He finds that it is distinguished from the Unionide by 
two posterior orifices, a rather long pallial sinus separating the 
branchial and pedal orifices; the mantle cavity is completely 
apaan into anal and branchial chambers by the branchiæ; and 
by the shapes of the labial palpi. The affinities are rather w 
Motela , Spatha, Triquetra, and other ee of the Genis 
Mutelidæ of H. and A. Adams. The terrestrial molluscan 
fauna of the region is not specially interesting, but that of the 
fresh-waters has been characterized as in its facies. 
this s aspect Pelseneer does not recognize. 
