612 EECORD OF CURRENT RESEARCHES RELATZNG TO 



peatris, Blaps mortisaga, Necrophorus vestigator, N. germanicus, Pierts 

 hrassicce (caterpillar), Periplaneta orientalis). 



2. Tyjie of Dytiscus. — Connectives extremely short ; transverse 

 commissure apjiosed to, but independent of, the sub-oesophageal 

 ganglion : wood-lice, dragon-flies, Phryganea, and various beetles. 



3. Type of Cossus ligniperda (first described by Lyonnet). — Con- 

 nectives of variable length ; transverse commissure springing from 

 the supra-oesophageal ganglion, together with or on the inner side of 

 the connectives, and closely embracing the gullet under the form of a 

 vertical sling or loop : various Myriopods, caterpillars, Orthoptera, 

 Coleoptera, and the larva of Tenthredo. 



4. l^ype of Suctorial Hexapods. — Connectives very short and 

 stout; transverse commissure under one perineurium with the sub- 

 cesojihageal mass : Hemiptera, adult Lepidoptera, and Diptera. 



Adult Hymenoptera did not give satisfactory results. Arachnids 

 remain to be examined. In Crustaceans it is known that the trans- 

 verse commissure passes on either side into a small ganglionic mass 

 from which fibres proceed to the brain. Similar centres, save that 

 they are closer to the brain, occur in Myriopods and Hexapods, as 

 shown by Leydig for Dytiscus. This commissure has, therefore, no 

 direct relation with the lateral " connectives." M. Lienard hopes to 

 show, in a future paper, the fundamental unity of arrangement of the 

 cephalic nervous centres throughout the Arthropoda. 



«• Insecta. 



Nerve-endings in Muscles of Insects.* — Dr. Foettinger asserts, 

 with Engelmann, the direct continuity of nerve and muscle. He 

 examined various beetles, caterpillars, and the cockroach. For his 

 modes of preparing these subjects we must refer to the original paper. 

 His researches were carried on in the laboratories of Professors 

 E. Van Beneden and Engelmann. 



The presence of a nervous network within the proper substance 

 of the muscle-cylinders is here denied. Each muscular fibre has 

 usually several nerve-end organs, or mounds of Doyere, beneath the 

 Barcolemma. Thus, Hydropliilus piceus may have six. Chrysomela 

 ccerulea showed nine of Doyere's cones in the space of one millimetre; 

 while in Passalus glaberrimus along thrice the same extent of muscle 

 but four or five could be counted. At the summit of Doyere's organ the 

 axis-cylinder divides into a number of fibrils, which, upon reaching 

 the base of the cone, immediately pass into the muscular substance 

 at the level of the intermediate disks. In this sense Dr. Foettinger 

 modifies the hypothesis of Engelmann (who saw some of his prepara- 

 tions) as to the connection between the ultimate nerve-fibrils and the 

 isotropic bands. One nerve may bifurcate to supply two of Doyere's 

 cones. From the apex of each of these as many as seven fibrils 

 sometimes diverge. The fibrils often seem to pass through the sub- 

 stance of the cone, at some distance from its surface, and a like 

 striated appearance is shown by cones which have been broken 



* ' Arch, de Biologie,' i. (1880) pp. 279-304 (1 plate). 



