ANATOMY, PHYSIOLOGY, ETC. 
Ech. 3 
23. Verrill, a. E. Note on some of the star-fishes of the New Eng- 
land coast. Am. J. Sci. (3) xi. pp. 416-420. 
Anatomy, Physiology, and Biology Generally. 
Biology. It is evident from the observations (2, 18, 19, 22) of different 
naturalists who have had the opportunity of studying the southern and 
antarctic Echinodermata during recent expeditions, or materials collected 
on those occasions, that very often, at least, there is no metamorphosis, no 
“ Pluteus ’’-like pelagic larval state, or “ locomotive bilateral pseudo- 
embryo” in these species; in place of that — as in several northern species 
— a direct development exists, and a commensal relation takes place 
between the parent and the brood, a passive maternal care at least being 
bestowed on the eggs and young, which are developed in or upon the 
maternal body until they have attained their definite shape and organiza- 
tion. Observations of this kind are, e.gr., made in Amphiuramagellanica., 
Ophiacantha vivipara and marsupialis, and Ophiomyxavivipara. In these 
Ophiuridm, the ova are developed in bags in the body-cavity, corresponding 
in number with the genital slits, through which they comraupicate with 
the exterior ; two or three young may be found in each bag, which receives 
the eggs from the ovaria. In Ophiacantha^ the young ones cling to the 
back of the mother until attaining a relatively considerable size. In the 
Holothurian Cladodactyla crocea^ the young may be found on the back of 
the mother, clinging in rows to the ambulacral feet of the ‘ bivium,’ 
which in the females are less developed than those of the ‘ trivium,’ or 
belly ; the dorsal ambulacral feet are also, in the young, developed after 
the ventral. In Psolus ephippifer^ the eggs are deposited and the young 
reared on the back, protected by the large polygonal scales of this portion 
of the body, which are in the females raised on stalks, and form in this 
manner a sort of ‘ marsupium.’ In Cidaris nutrix^ the young are reared on 
the peristome, protected by the spathulate spines of the peristomial part 
of the shell,while in Goniocidaris canaliculata^memhranipora, and vivipara, 
the nursery is established at the abactinal portion, protected by the 
large uppermost primary spines. In Hemiaster {Abatus cordatus and 
excavatus), the widened and deepened paired ambulacra of the mature 
females (in the young and in the males they are not so dilated 
nor so deeply sunken) perform the same functions. In Asterias 
perrieri, a cluster of some hundreds of young ones may be found clinging 
to the ventral disk of larger specimens. In Archaster excavatus, the eggs 
pass from the ovarian openings into the interspaces between the shafts of 
the “paxilli;” when six ambulacral suckers at least are formed on each 
arm, the young star-fishes push their way out between the “ paxilli,” and 
remain for a time loosely attached to the parent by the centre of the 
dorsal surface, clustering especially in the angles between the arms of the 
mother. In Hymenaster nobilis, a marsupial tent is formed over the vent 
by five specially developed dermal valves, supported on spines, like the 
rest of the superficial covering of the starfish. During the southern 
cruise of the “Challenger,” between the Cape of Good Hope 'and 
Australia, only one form of Echinodermal “pseud-embryo” (a Chiridota, 
