296 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Echinoderma. 
Asteroidea of the North Atlantic.* — M. E. Perrier describes some 
of the Asteroidea obtained by the Prince of Monaco from the North 
Atlantic. Thirty-five species were collected, representing 27 genera. 
Six of the species were new, — Pedicellaster parvulus, Stolasterias neglecta , 
Prognaster Grimaldi * , Calycaster monoecus , Sclerasterias Guernei , and 
Hexaster obscurus. The last four should form types of new genera, and 
are discussed in some detail. 
Deep-Water Ophiuridae from the Indian Ocean. f— Dr. B. Kohler 
gives a preliminary summary of his examination of the deep-water 
Opliiuridee collected by the ‘ Investigator * in the Indian Ocean. Fifty- 
five species were included in the collection, 51 Ophiuridae and four 
Astrophytonidae ; and of these 39 are new. He directs particular atten- 
tion to Ophiotypa simplex g. et sp. n., a remarkably simple form, in fact 
the simplest as yet known. It was also found at the Azores. Other- 
remarkable new forms are — Ophiopyrgns Alcocki, the second species of 
this genus, Ophiomastus tumidus, Ophiopyren bispinosus, Pectinura con- 
spicua with a very large disc, Opliiochiton ambulator with very long 
arms, &c. Atlantic forms were sparsely represented, but there were 
not a few already known Indo-Pacific forms. The absence of some 
widespread abyssal species, such as Ophiomusium Lymani , was striking. 
Use of the Anchors in Synapta. f — Herr Hj. Ostergren has made u 
study of this problem. In 1842, Qaatrefages suggested that the anchors 
of Synapta helped somehow or other in locomotion. Semper rejected 
this possibility, and asked whether they might not aid in tactile function. 
Cuenot showed that this could not be, but suggested that the anchors 
were raised (by pressure of the body-fluid) on the parts of the body 
which were for the time most stretched. But the fact is that the anchors 
on such parts are rather depressed than raised. 
Ostergren has examined about 30 species of Synapta , and believes 
that certain important structural characters of the anchors have been 
overlooked. As is well known, the anchors in Synapta are always con- 
nected with plates, the anchor resting with one end upon the plate which 
lies in a deeper stratum of the skin. 
Each anchor has three main parts, the handle, the shaft, and the 
bow. The arms of the bow, as H. Lyman Clark also observed (1896),. 
do not lie in the same plane as the shaft, but in one which forms an 
acute angle therewith, and always so that the points of the arms are 
directed outwards from the anchor-plate. In all the species examined, 
the anchors lay transversely to the longitudinal axis of the animal, 
parallel to the circular muscles. 
The author proceeds to show in what seems conclusive detail that 
the anchors do assist very materially in locomotion by gripping the 
surface on which the animal moves. They also help in fixing the bur- 
rowing Synapta. 
In Ankyloderma , the quite different anchors help in the attachment 
* Kesultats des Campagnes Scientifiques, fasc. xi. (1896) 57 pp., 4 pis. 
t ZooJ. Anzeig., xx. (1897) pp. 166-70. 
$ Tom. cit., pp. 148-59 (7 pis.). 
