IO12 General Notes, [October, 
Soc. London, 1884) gives a monograph of the genus Oreaster. 
He allows twenty-seven species, including Nidorellia armata of 
Gray, and gives a full description of each, with habitat, etc. 
Mollusks—Dr. Gwyn Jeffreys (P. Z. S) describes seventy-four 
species of Littorinidz, Scalaride, etc., gathered by the Lightning 
and Porcupine expeditions. large proportion are new 
Professor B. Sharp, in an address before the Biological section of 
the Academy of Natural Sciences of Philadelphia, gives the fol- 
lowing as the development of the molluscan eye: (1) A pigmen- 
tal surface of epithelial cells, as in Ostrea; (2) pigmented invagi- 
nated grooves for protection at centralized points of the body, 
each visual, all having a cuticular body, as in Solen vagina and S. 
ensis ; (3) a sphere made of pigmented cells, the sphere formed 
by the contraction of the groove, as in Patella; (4) a cuticular 
lens formed by the centralization of the refractive bodies of each 
Mr. Chas. E. Beecher (36th report N. Y. State Mus. 
Nat. Hist.) describes some abnormal and pathologic forms of 
fresh-water shells. He figures a sinistral Planorbis exacutus, 
Fishes —Mr. W. R. O. Grant (Proc. Zodl. Soc., 1884), contrib- 
utes a revision of the fishes of the genera Sicydium and Lentipes. 
The first genus occurs throughout the torrid zone in fresh waters 
near the sea, and contains twenty-four species, five of them new 
to science. Lentipes occurs in the rivers of the Sandwich islands, 
and equals Sicyogaster Gill. Two species are known. 
Reptiles—Professor W. K. Parker (Trans. Zod]. Soc. London, 
1883), in his account of the structure and development of the skull 
_in the Crocodilia, remarks that the skull of the Sauropsida is a mere 
specialization of the underlying ichthyic type. He considers that 
-in some very important things the skull of the anurous Amphibia 
_ forms a better leading step to the mammal than that of the Sau- 
ropsida. e Crocodilia show in the earliest stage a compound 
nasal labyrinth. Only three of the visceral arches are developed, 
ad only the first attains full size. In embryos from one and five- 
