19(3 SUMMARY OF CURRENT RESEARCHES RELATING TO 



INVERTEBRATA. 



Mollusca. 

 o. Cephalopoda. 



Genera of Dibranchiate Cephalopoda.* — W. E. Hoyle has prepared 

 a list of the generic names with their type species, which will be of much 

 service to future enquirers. In each case the ground upon which the 

 type has been selected is stated, ami whenever the author is certain that 

 the type specimen of the type species exists in a particular collection, the 

 fact is stated. 



£. Gastropoda. 



Glands and Luminescence of Phyllirhbe.t — E. Trojan describes two 

 kinds of gland-cells in the body-wall : mucus-cells and albumin-cells, 

 the former inclining to be multicellular, the latter always single. There 

 are chromatophores with numerous pigment-granules, functioning like 

 those of Cephalopods. On the lips there are particularly large mucus- 

 glands, which take the place of salivary glands. There are unicellular 

 and multicellular integumentary sense-organs. The luminescence 

 requires stimulus. It is of two kinds, diffuse and restricted, the former 

 due to mucus-cells, the latter to combinations of these cells in clusters. 

 The luminescence is extracellular. The animal is probably poisonous, 

 and the luminescence a warning. 



Minute Structure of Phyllirhbe bucephala.J— Ernst Born has 

 made a detailed study of the minute structure of this pelagic Gastropod. 

 He gives an histological account of the skin, the pigment-cells, the 

 nervous-system, the sense-organs, the musculature, the glands, the 

 vascular system, and the excretory structures. 



Abnormal Shells of Achatina.§ — H. Rolle describes and figures 

 some remarkable abnormal shells of Achatina, such as a sinistral spiral 

 and an extraordinary scalariform shell. 



Blood-vessels and Nerves of Jlolididse and Tritoniadae.||— Thos. F. 

 Dreyer has studied a number of different genera in these two families of 

 Gastropods. In no artery, vein, or lacuna was a proper epithelium 

 discernible. All these were lined by a membrane composed of much- 

 branched cells. In both families the heart contains mixed blood. The 

 cerata are specialized respiratory organs. In the Tritomadas there are 

 blood-glands at the base of the afferent branchial veins. The nerves 

 (except the acoustic and optic) are mixed nerves, united at the periphery 

 by a nerve-plexus of small much-ramified cells. The neuropile breaks 

 up into a number of bundles. Every ganglion-cell has a large thick 

 neurite, and probably numerous dendrites. There is a perinuclear net- 

 work of neurofibrils from which fibrils extend to the periphery and then 



* Abh. Senckenberg Nat. Ges., xxxii. (1910) Festschr. Kobelt, pp. 407-13. 



t Arch. Mikr. Anat., lxxv. (1910) pp. 473-518 (2 pis. and 4 figs.). 



X Zeitschr. wiss. Zool., xcvii. (1910) pp. 105-97 (5 pis. and 2 figs.). 



§ Abh. Senckenberg Nat. Ges., xxxii. (1910) Festschr. Kobelt, pp. 191-3 (1 pi.). 



|| Zeitschr. wiss. Zool., xcvi. (1910) pp. 373-418 (4 pis. and 4 figs.). 



