ZOOLOGY AND BOTANY, MICROSCOPY, ETC. G89 
refraining from naming any of them as “new species”; to work out a 
collection of Ophiotriches almost unlimited leisure is necessary. Reasons 
are given for supposing that colour must be considered as an unreliable aid. 
One of Mr. Bassett-Smith’s best finds was a fairly large supply of the 
interesting Ophiopteron elegans described by Prof. Ludwig in 1888, in 
which the arm-spines are connected by a membrane, so that they seem 
to form a kind of wing. 
Throughout the paper there are scattered references to the theory, 
now a little discredited, as to the homologies of the calycinal plates of 
Crinoids with the apical plates of other Echinoderms ; the test of a 
young Culcita only 12 mm. in diameter has been carefully mapped out 
with the hope of getting some light on the morphology of the skeleton, 
but in this the author confesses himself disappointed. 
Illustrations of Indian Echinoderms.* — Under the authority of the 
Director of the Royal Indian Marine, and the direction of Dr. A. Alcock, 
the first part of the atlas of figures of Echinoderms described recently 
from the Bay of Bengal has lately been published. The three plates 
which have appeared are devoted to Asteroidea. 
Asteroidea.} — Prof. H. Ludwig is to devote the second volume of his 
work on Echinoderma to the Asteroidea, and has just published the first 
two parts. The bibliographical list, which appears to be quite up to 
date and exceptionally well done, includes nearly six hundred titles. 
The history of our knowledge of the group is rapidly but adequately 
sketched, and the author then enters on an account of the morphology 
of the class. The form, the size, the colour, the external consistency 
are first dealt with. In treating of the skin, its layers and glands are 
described. Of the dermal appendages the most important are the 
pedicellariae, which are divided into those that are stalked and those that 
are sessile; the former are either crossed or straight, and the latter 
forceps-like or alveolar. The cribriform organs of Sladen are thought 
to be morphologically identical with the ciliated spines of the Astro- 
pectinidae, for they have essentially the same structure, and in all cases 
are placed on the vertical sutures of the marginal plates. 
In his account- of the skeleton Prof. Ludwig thinks it best to avoid 
the use of terms which indicate homologies to parts of the Crinoid or 
Ecbinoid skeleton, such as “ basalia *' or “ calicinalia,” and he uses 
strictly objective terms ; thus the ambulacral skeleton consists of ambu- 
lacral, adambulacral and superambulacral pieces, and the region of the 
mouth is called the peristome. The interambulacral skeleton consists 
of the inner intermediate piece, the ventro-lateral and the lower mar- 
ginal plates, while the antiambulacral skeleton consists of the upper 
marginal plates, the terminals, the primary plates of the back of the disc, 
the secondary radial plates of the arms and disc, the dorso-lateral, sup- 
plementary, and madreporic plates. 
Mesozoic Echinoderma of the United States.} — Mr. W. B. Clark, 
in continuation of the valuable work of Messrs. Wachsmuth and 
* ‘ Illustrations of the Zoology of the Royal Indian Marine Surveying Steamer 
Investigator . . . Echinoderma,’ I. pis. i.-iii. Calcutta. 4to, 1894. 
f Bronn’s Klassen u. Ordnungen, II. 3, parts 17 and 18 (1894) pp. 461-540 
(6 figs.). } Bull. U.S. Geol. Survey, No. 97 (1893) 101 pp. and 50 pis. 
