46 SUMMAEY OF CURRENT RESEARCHES RELATING TO 



posed by the autliors. The depths varied from 70 to 1215 fathoms 

 and the'latitude from 63° 5' N. to 73° 47' -5 N. 



Organization and Development of the Gordii.* — M. A. Villot (in a 

 second note) describes the atrophy of the digestive organs, and the 

 development of the genital organs, and of some other systems. In 

 the integument he can detect only two layers, one superficial, structure- 

 less, and not coloured ; the other formed of connected elastic fibres 

 more or less strongly coloured. The second or lower layer is not 

 dififerentiated till towards the end of the second larval period. The 

 author now explains how it is that the different parts of the nervous 

 system are found in the adults to be continuous. In the larva of 

 Gordius there is no cerebroid organ, but there is an oesophageal 

 ring exactly comparable to that which is found in the Nematodes. 

 When the oesophagus disappears, as it does in the adult Gordius, 

 the nerve-centres unite into a cephalic ganglion. This important 

 character appears to the author to be a sufficient justification for 

 the formation of a sj^ecial order for the genus Gordius, which 

 would be intermediate between the " Helminthes " and the Gephyrea. 

 There is always an extremely close connection between the epidermis 

 and the nervous system. The general structure of the nervous 

 system seems to be somewhat remarkable, inasmuch as the author 

 states that, in certain conditions, it has the appearance of a true 

 vascular system ; water penetrates into it very easily ; the cells of the 

 hypodermic plexus dilate and become pyriform in shape, while the 

 epidermis of the papillae swells and becomes pushed out to the exterior. 

 It is these processes which Von Siebold and the author have taken for 

 parasitic algte. 



The development of the muscular system is simple. The myoblast 

 loses its spherical and takes on a ribbon-shaped form ; the envelope 

 of the cell forms the myolemma, and the contents the contractile sub- 

 stance. This condenses against the cell-wall, and becomes divided 

 into longitudinal fibrillae, which run parallel to the long axis of the 

 fibre. This mode of formation of the muscular elements is said to be 

 most marked in the Polygordiida. 



The atrophy of the digestive apparatus consists chiefly in the dis- 

 appearance of the mouth of the oesophagus. The secreting organ 

 described by Meissner is nothing but the intestine, which ends 

 anteriorly by a delicate Cfecum, and posteriorly by opening into the 

 cloaca. Part of the parenchyma of the adult always retains the 

 characters of the embryonic tissue, while the rest is converted into 

 connective tissue or cartilage. The arrangement of these layers can 

 best be seen in transverse sections of the female cloaca. 



Nematoid Parasitic in a Bat.t — Dr. Macdonald gives an account 

 of a worm, to which its discoverer — Dr. Dobson — has given the name 

 of Pterygodermatites'l Macdonaldi. It was at first sight thought to be 

 Annelidan,§ but Dr. Macdonald now recognizes its Nematoid character; 



* Comptes Rendus, xci. (1880) pp. 774-6. 

 t Ann. and Mag. Xat. Hist., vi. (1880) p. 409. 

 + An older generic name is Rktularia. 

 § ' Nature.' xxii. (1880) p. .583. 



