370 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
on account of their homogeneous contents and yellowish-brown colour. 
In addition to the elements directly derived from the epithelium there 
are others which are shown by their position and structure to be 
nervous. At the base of each sensory organ there is a nerve-fibre, 
connected with a plexus which lies in the connective tissue ; these fibres 
appear to be feebly differentiated as compared with the nervous elements 
of Vertebrates. 
The cutaneous glands of Sipunculus nudus, which are scattered over 
the whole body, are specially numerous on the proboscis, and least 
numerous near the hinder end of the body. There is considerable 
variety in the form and contents of these glands, but there is no doubt 
that they are all derived from the general epithelium. They are all 
coloured pale rose by alum-carmine after treatment with osmic acid. 
The whole surface of the body of Phascolosoma elongatum is covered by 
small warty projections, and the glandular or sensory elements are found 
in one and the same follicle. Each of these organs is formed of a cavity 
hollowed out in the cuticle and lined by flattened epidermic cells, 
similar to those of the rest of the body. They are in connection with 
the subjacent layers by a hollow pedicle ; in the lumen of the canal 
there are one or more nerve-fibres. 
In conclusion, a short account is given of the sensory and glandular 
corpuscles of Aspidosiphon scutatum and Phascolion strombi. The general 
surface of the body being sheltered by the walls of old tubes of Serpulae 
or shells of Molluscs is less sensitive than in the preceding forms ; the 
proboscis, on the other hand, is a very delicate sensory organ ; its 
sensory corpuscles are formed by groups of small rod-shaped cells, but 
the author was unable to trace any nerve-fibres into them. 
Echiurus chilensis.* — Dr. A. Collin describes the original specimen 
in the Berlin Museum to which Max Muller referred in 1852. It is a 
distinct species, and the title Echiurus chilensis , which has found a place 
in the literature of Echiuridse, should be retained. The species need not 
be described here, save in so far as that is done in saying that it closely 
resembles Ech. unicinctus v. Drasche except in its large size (6 ^ in. in 
length), and in having three pairs of segmental organs. 
0. Nemathelminthes. 
Development of Gordius. f — M. A. Villot gives a general, historical, 
and critical account of the development of Gordius, a subject to which he 
has devoted much attention. He finds that everything tends to demonstrate 
the truth of his original statement that Gordius, like Mermis, is developed 
in one host only ; he would, indeed, go further and affirm that the 
encystation of the embryo is not a necessary phase in the development 
of this form. In the history of the second or larval stage there is 
nothing w'hich can be compared to the process of alternation of genera- 
tions. The development is a true metamorphosis, not without analogy 
to that which is seen in Mermis and Echinorhynchus. Gordius has, 
however, not had its primitive organization so profoundly modified by 
* Zool. Anzeig., xiv. (1891) pp. 463-4. 
t Ann. Sci. Nat., xi. (1891) pp. 329-401 (3 pis.). 
