ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
545 
and Polyps of the West Indies have been carried to the Bermudas ; and 
“ we can well imagine an equatorial current taking during Miocene and 
Eocene periods the young of the Echini flourishing in the Crag and in 
the Mediterranean, and in the southern extension of that fauna perhaps 
only from the Cape Yerd Islands, and bringing them to the shores of 
Northern South America or into the Caribbean Sea.” 
Holothuroidea of the ‘ Travailleur ’ and ‘Talisman’.* — M. Remy 
Perrier makes a second report on this collection, dealing with 31 species, 
15 of which are new. The whole collection included 46 species, 26 new. 
The family Holothuriidae is divided into two tribes, — Synallactinae and 
Holothuriinae (Ludwig), the former mostly abyssal, the latter mostly 
littoral. The Synallactinae, diverging at an early date from the Holo- 
thuriinae, as their primitive characters suggest, migrated to great depths, 
and gave rise to the specialised group of Elasipoda. 
Chilian Holothuroids.j — Prof. H. Ludwig reports on Plate’s collec- 
tion. There were only six species, which suggests the sparseness of the 
Chilian littoral fauna. 
Descriptions of Holothuria platei sp. n., of Chiridota fernandensis 
sp. n. (from Juan Fernandez), aud of some previously recorded forms, 
are given. 
A comparison of the Chilian and the Magellan Holothurians yields 
the surprising result that the number of genera and species increases 
towards the South. 
Variation in Ambulacral System.!— Mr. II. L. Osborn describes 
the test of a specimen of Arbacia punctulata in which the number of 
ambulacral systems was four instead of five. One entire ambulacral 
system and the neighbouring inter-ambulacrals had failed to appear, 
but the apical organs were not included in the suppression. 
Larval Stage of Luidia.§ — Prof. W. C. M‘Intosh gives a brief 
account of the remarkable Bipinnaria asterigera , the larval stage of a 
species of Luidia, specimens of which were obtained in St, Andrews 
Bay. 
Hybrid Echinoid Larvae. || — Mr. II. M. Vernon has made experi- 
ments on the hybridisation of Strongylocentrotus lividus, Splicer echinus 
granularis , aud Echinus micro-tuberculatus, and other Echinoids, his 
object being to determine the exact relationship of structure and size 
between certain of the hybrid and parent larval forms. One of the most 
important of his results is stated as follows : — The Strongylocentrotus 9 
— Splicer echinus $ hybrid is only formed at a time when the Strongylo- 
centrotus ova have reached their minimum of maturity ; whilst in the 
case of the reciprocal hybrid, it follows that, as the maturity of the 
Strongylocentrotus-spQTm. increases, it is able to transmute first a por- 
tion and then the whole of the hybrid larvae from the Sphcerechinus to 
its own type. In other words, the characteristics of the hybrid offspring 
depend directly on the relative degrees of maturity of the sexual pro- 
ducts. 
* Comptes Rendus, cxxvi. (1898) pp. 1664-6. 
t Fauna Chilensis, Heft ii., Zool. Jnhrb., Supplement iv. (1898) pp. 431-54 (1 pi.). 
X Amer. Nat., xxxii. (1898) pp. 259-61 (1 fig.). 
§ Ann. Nat. Hist., ii. (1898) pp. 103-18 (1 pi.). 
|| Proc. Roy. Soc., lxiii. (1898) pp. 228-31. 
