232 



SCIENCE. 



[Vol. I., No. 8. 



obvious. By Vaillant it is thought "that the fish 

 presents relations with the Anacanthini, with certain 

 Physostomi (such as tlie Scopelidae and Stomiatidae), 

 and also with the Apodes." It has, in fact, features 

 of resemblance with the forms noted, as well as with 

 the Saccopharyngidae, but they are wholly superficial. 

 Assuming, of course, the correctness of the charac- 

 ters attributed to Eurypharynx, we are compelled to 

 regard it as the representative of a primitive type 

 of fishes, and perhaps of a peculiar order related 

 to the dipnoan and ganoid series. The examination 

 of the brain, heart, viscera, and skeleton, especially 

 the skull and scapular apparatus, will doubtless defi- 

 nitely determine its relationships. — {Comptes rendus, 

 Dec. 11, 1882; Ann. mag. nat. hist. (5), xi. 67.) T. G. 



[520 



Development of the caudal region in lizards. 



— H. Strahl publishes a renewed investigation of the 

 development of the neurenteric canal, allantois, and 

 tail, in lizards. His researches were made on Lacerta 

 agilis. The early embryonic disk consists of an ante- 

 rior field in which the medullary groove is subse- 

 quently developed, and a posterior field containing 

 the mass of cells forming the primitive streak. From 

 the ectoderm of the front part of the streak is formed 

 an invagination, which deepens and descends ob- 

 liquely forwards. For some time the cells lining the 

 invagination do not present a distinctly epithelial 

 character, which leads Strahl to consider this lining 

 mesodermie. The lower wall of the canal, thus 

 formed, breaks through, establishing a connection 

 with the entodermio cavity. The axial row of cells 

 in the dorsal wall of the canal becomes elongated, 

 making a thickened epithelial band, which is the 

 <xnlage of the notochord. This anlarje gradually ex- 

 tends itself farther forward. The neurenteric canal 

 marks the hind limit of the medullary canal and of 

 the chorda, and moves backward during further 

 growth. It is entirely surrounded by mesoderm of 

 the primitive streak. After the complete closure of 

 the neural tube the neurenteric canal closes also. 

 The primitive streak is directly concerned in the for- 

 mation of the tail and of the allantois. The latter 

 first appears as a solid mass of cells, which afterwards 

 grows out into the pleuro-peritoneal space, and be- 

 comes hollowed. Tlie chorda becomes separated 

 from, and overgrown by, the entoderm, in the same 

 manner as has been previously observed in other ver- 

 tebrates. The caudal gut (schwanzdann) lasts rela- 

 tively long. Its communication with the intestine is 

 aborted, but the connection with the neurenteric 

 canal continues longer. Strahl argues against Kiipf- 

 fer's view that the neurenteric canal is directly con- 

 cerned in the formation of the allantois. He also 

 believes the homology drawn by Balfour between the 

 primitive streak and neurenteric canal on the one 

 hand, and the bl.astopore of fishes and amphibia on 

 tlie other, to be erroneous. (His arguments on the 

 latter point seem very defective, nor does he appear 

 to thoroughly grasp the problem.) — (Arch. anat. 

 physiol. ; anat. abtk., 1SS2, 242.) c. s. M. [521 



Permian reptiles. — Professor E. D. Cope exhib- 

 ited additional lemaius of Permian reptiles belonging 

 to the genera DiadecLes, Empedias, and Helodectes. 

 The scapular arch of Empedias molaris resembles 

 that of tlie carnivorous type in having a very small 

 coracoid bone. Tlie episiernum is very robust, and, 

 ceasing at the anterior part of the arch, does not 

 separate the clavicles below. The claws approach 

 the ungulate type, and are admirably fitted for dig- 

 ging and shovelling. The vertebrae possess the hy- 

 posphen first observed in the Jurassic reptilia. In 



the Permian diggers this process formed a strong 

 articulation between the vertebrae for the purpose of 

 resisting shock; while, in the swimming Jurassic 

 forms, it served to counterbalance the necessary light- 

 ness of the bones. The presence of such a structure 

 in these two very distinct forms of life furnishes an 

 interesting exami^le of the employment of the same 

 means to provide for varying necessities. The basi- 

 occipital presents the usual reptilian articulations, 

 and was lost from the specimens before described, 

 which were supposed to have four articulating facets. 



— (Acad. nat. sc. Philad.; meeting March 13.) [522 



Mammals. 



Tongue of Perameles; origin of taste-bulbs. 



— The tongue of Perameles nasuta, a rare marsupial, 

 contains numerous and remarkable sensory organs, 

 which have been investigated by Edward B. Poulton. 

 Towards the base of the tongue are three circumval- 

 late papillae; the taste-bulbs, numbering 700 or more, 

 lying in the papillary wall of the valla. In the papillae 

 and around them are numerous serous glands. The 

 axis of each papilla is formed by large ganglion, 

 which contains only a few but very large cells, and 

 gives off non-medullated fibres to the taste-bulbs. 

 This is an important observatiori, since in the organs 

 of sight and hearing there always intervene ganglion 

 cellsbetween the sensory apparatus and the central 

 nervous system. May it not be also the case with all 

 the gustatory organs? The taste-bulbs are compara- 

 tively simple, and appear to contain only one kind of 

 cell. The fungiform papillae are chiefly arranged on 

 each side in a single, irregular line; they very rarely 

 contain laste-cells; but occasionally a few are found, 

 wliich may lie close together, but are not united into a 

 distinct taste-bulb. His observations have led Poul- 

 ton to formulate the following theory of the origin 

 of taste bulbs: the terminal organs in the mouth 

 would be placed like similar organs in the skin; 

 namely, in papillary ingrowths of the mucosa; hence 

 the ceils would lie together, and, in assuming the co- 

 lumnar form, they would converge towards the outer 

 surface of the skin. The convergence of the cells 

 would soon lead to their union into a bulb. One more 

 step: differentiation of the central and peripheral co- 

 luuimar cells of the bulb would produce the gustatory 

 organ of the higher mammalia. " This account of 

 the origin of taste-bulbs explains one important dif- 

 ference between them and tlie other structurally 

 related end-organs, as those of the olfactory region, 

 or sacculi and ampullae; i.e., in the fact that the 

 gustatory cells are massed together in little groups 

 surrounded by protective cells, while the auditory 

 cells in the positions above mentioned, and the olfac- 

 tory cells, are isolated, each being separately pro- 

 tected by columnar cells. This difference, it appears, 

 is simply due to the latter elongating from a tolerably 

 plane surface, while the gustatory cells have elongated 

 from the curved surface of an interpapillary process, 

 . . . and therefore have met and penetrated the sur- 

 face in a group." 



At the sides of the tongue are long filiform papillae 

 with an axial non-medullated nerve; and over the 

 upper surface are very numerous peculiar papillae, of 

 small size, and surrounded on the summit by a ring of 

 fine, hair-like papillae, generally ten in number ; but 

 towards the liack of the tongue the hairs disappear on 

 the anterior side, and at last, on the papillae farthest 

 bncK-, there aie only two hairs left. The top of the 

 main papilla is concave. The author describes the 

 interesting histology of these organs; but for further 

 details we must refer to the v.aluable original.— (Quart. 

 journ. microsc. sc, xxiii. 69). c. s. M. [523 



