No. 379.] REVIEWS OF RECENT LITERATURE. 527 
sion is that the easiest explanation of these facts would be to regard 
this lake as having been a deep arm of the sea at least as late as 
tertiary times, and that its animals are the descendants of a former 
marine fauna. The delicate nature of the medusz of the lake, and 
the fact that its molluscs are deep-water forms, renders it impossible 
that they have migrated into the lake under existing conditions. 
The Species of Millepora. — Thirty-nine so-called species of 
Millepora, the stag-horn coral, have been described from the seas 
of the world. Dr. Hickson, of Manchester, read a paper at the 
meeting of the Zodlogical Society of London, on April 5, in which he 
stated that the characters hitherto used for the discrimination of 
species have proved of no value, and it is believed that but one 
species exists, the various forms being due to the conditions under 
which the individuals lived. 
Centrosome in Myzostoma.— Kostanecki has recently investigated 
the early phenomena of the egg of Myzostoma glabrum (Arch. mikr. 
Anat., Bd. li). The most important statement made is that the cen- 
trosomes of the first cleavage spindle arise, as in other Metazoa, from 
the male centrosome, a result in conflict with Wheeler’s previous 
studies, 
Hermaphroditism of Crepidula. — Prof. E. G. Conklin, who has 
long been studying the embryology of Crepidula, concludes that this 
genus affords another case of protandric hermaphroditism and of 
marked sexual dimorphism. 
Palzospondylus. — A few years ago Dr. R. H. Traquair described 
under this name a small fossil from the rocks of Scotland, which he 
regarded as a fossil cyclostome. Dr. Bashford Dean concluded a 
little later that a specimen in his possession showed traces of paired 
fins, a fact which threw doubts upon its cyclostome affinities. Dr. 
Traquair replied to the effect that the markings around the fossil, 
regarded by Dr. Dean as indicating the existence of paired fins, were 
due to inorganic agencies. At the meeting of the Zodlogical Society 
of London, on April 19, Dr. Dean presented a paper supporting his 
views, while Mr. A. Smith Woodward, the eminent authority on fossil 
fishes, stated that he was inclined to agree with Traquair in his 
interpretations. The question is one of great interest, and the last 
word has yet to be said upon it. 
