Ech. I 
ECHINODERMATA. 
BY 
B. A. Minchin, B.A. 
INTRODUCTION. 
The number of titles (186) in the Echinoderm literature for 1891 is 
exceptionally large, and the year is no less remarkable for the number 
of important additions to our knowledge of the group which have been 
brought forward. 
In Morphology, Ludwig (1) discusses the anatomy of Anlcyroderma , 
and Ludwig & Barthels give a preliminary account of the results of 
their investigations on the Synaptidce. Perrier (1) concludes his 
elaborate memoir on the organization of Antedon. Important statements 
bearing on the morphology of fossil Crinoids will be found under 
Bather (1,2,5), Jaekel(1,2), and Wachsmuth & Springer. Perrier 
(4) obtains important results from a study of the young of Asterias 
spirabilis , and their mode of attachment to the mother. Durham has a 
new explanation of the homologies of the ovoid gland and axial sinus, 
for which see also Perrier (4) and Cuenot (1). Carpenter leaves us a 
valuable memoir on the morphology of Cystidea. Finally, Cuenot (1) 
publishes his views on Echinoderm morphology in a prolix paper, contain- 
ing comparatively little original observation. 
The most important embryological papers of the year are those of 
Ludwig (3, 4) on the development of Cucumaria. Brooks & Field have 
valuable observations on the larval development of Asterias. Russo 
(2, 3, 5, 6) has a number of papers on the development of Ampkiura 
sguamata. The interesting observations of Fol on the fertilization of 
the ovum of Asterias are of far-reaching significance. Driesch and 
Fiedler have experimental observations on the segmentation of the 
ovum in Echinoderms, and Pictet studies with great care the spermato- 
genesis of various Echinoids. Of considerable interest are the observations 
of Chadwick on reproduction by Fission in Cucumaria. 
1891. [VOL. XXVIII.J F 1 
