ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 137 



■consists of " chi'omaffiue " cells, forms with its fellows the supra-renal 

 body. Of the ganglia as first formed, the first five (I-V) disappear 

 during the early stages of development ; the next ten or eleven (VI- XV 

 or XVI) fuse to form one large ganglion, with simultaneous degeneration 

 of the first five of them (VI-X). From the fifteenth or sixteenth ganglion 

 onwards, the ganglia persist as definite structures. In regard to the 

 question of the existence of a sympathetic nervous system in the head, 

 the author points out that a difficulty in the comparison of cranial and 

 spinal nerves seems to lie in the non-applicability of Bell's law to the 

 former. He suggests that an explanation of this apparent anomaly may 

 be found in the supposition that the cranial nerves, no less than the 

 spinal, have arisen by the union of sensory and motor elements ; but 

 while in the latter case the union takes place outside the central nervous 

 system, in the former it takes place within. In consequence, the large 

 peripheral ganglia of the dorsal cranial nerves must be supposed to 

 contain sympathetic elements, and the nerves must contain sensory, 

 motor, and sympathetic elements. Where, as in the higher Vertebrates, 

 special " sympathetic " ganglia exist in the head, the ganglia must con- 

 tain cerebro-spinal in addition to sympathetic elements. In Selachians the 

 interrenal organ arises in connection with the tubules of the mesonephros, 

 and is thus contrasted with the suprarenal ; but the author is not per- 

 fectly convinced that it can be regarded as completely homologous with 

 the cortical part of the adrenal of Birds and Reptiles. In Selachians 

 the interrenal arises entirely behind the developing genital organ ; in 

 Birds and Reptiles the cortical part of the adrenal has a close relation to 

 the genital organ ; a distinction to which considerable importance is 

 attached. 



Post-Larval Changes in Vertebral Articulations in Salamanders.* 

 — J. Percy Moore notes that in Spelerpes ruber, for instance, the verte- 

 brae are both osteologically and physiologically "amphiccelous during 

 late larval life and for a time after the metamorphosis ; that during the 

 prime of life they are still amphiccelous as far as the strictly bony 

 portions of the centra are concerned ; but if, as seems more logical, the 

 cartilaginous structures also are considered, they cannot be characterised 

 otherwise than as opisthoccelous ; and that in old age they are opistho- 

 ccelous. There is thus a progress throughout life from a primitive to 

 a more specialised type. Similar changes occur in Desmognaihus fusca 

 and other forms. 



Development of Teleostean Vertebral Column f — S. Ussow con- 

 trasts the Teleostean vertebral column with that of Selachians and 

 Holostei. In Selachians the vertebra arises entirely at the expense 

 of the cartilaginous elements of the bases of the arches, the fibrous 

 sheath of the notochord serving as the locus of development. In 

 Holostei it developes similarly from the cartilaginous elements of the 

 arches, and also at the expense of the intercalaria and an independent 

 ossification of the perichordal connective-tissue, which unites the arch- 

 bases with the intercalaria, and covers with a bony layer the peripheral 

 portions of the fibrous notochordal-sheath in the parts free from the 

 cartilage of the arch-bases. Thus the vertebra rises not in, but over aud 



* Proc. Acad. Nat. Sci. Philadelphia, 1900, pp. 613-22. 

 t Bull. Soc. Imp. Nat. Moscou, 1900, pp. 175-240 (4 pis.). 



