304 SUMMARY OF CURRENT RESEARCHES RELATING TO 



neura (Acanthochites fascirularis) and in the protobranch Nucvla, and 

 show that the degree of differentiation does not in general correspond 

 with phyletic position. It has of course to do with the functional activity 

 of the heart, which differs even among related forms in correspondence 

 with the conditions of life. In the Chiton the musculature of the heart 

 consists of a plexus of fibrils which do not form individualised fibres. 

 Most of the fibrils are simply striated ; a few show compound striation, 

 and some appear homogeneous. In the protobranch the musculature is 

 feebly developed ; there are a few delicate bundles of simply striated 

 fibrils ; there are no definite fibres. 



Histology of Molluscan Heart-Muscle.* — P. Vigier and F. Vies 

 have failed to find any relation between the perfection of striation of 

 the heart-muscle of molluscs and the phylogeny of the group. The 

 degree to which it exists in particular forms has a purely functional 

 significance, and it is suggested that the striation described by Marceau 

 in the heart of Octopus is not characteristic of Cephalopods in general. 



a. Cephalopoda. 



Egg-Envelopes in Cephalopods and Chitons.f — A. Schweikart 

 describes the formation of the egg and the follicle-cells in Cephalopods, 

 the three ovarian egg-envelopes in Todaropsis veranii and Eleclone 

 moschata, the peculiar conditions seen at the animal pole of the egg of 

 Eledone when the micropyle is being formed, the development of the 

 true chorion from the follicular epithelium in Sepiola rondeletii, and the 

 formation of the micropyle in Kossia macrosoma. 



In five species of Chitonidae the ovum first acquires a chorionic 

 membrane as a secreted product of the follicular cells, and afterwards a 

 vitelline membrane which arises as a peripheral hardening of the 

 peripheral zone of the egg-cytoplasm. 



7. G 1 £ \ 1 c 1 c c" a 



Physiological Studies on Aplysia.J — W. Straub shows how well 

 this mollusc is adapted for physiological studies on heart-beats, blood- 

 pressure, respiration, innervation, and so on. His communication is 

 simply an illustration of physiological method applied in a more or less 

 unexplored field. 



New Genus of Solenogastres.§— H. Heath describes a new genus 

 from Alaska, Limifossor, g. n., and species L. talpoideus, sp. n. In the 

 arrangement of the organs in the posterior end of the body, the form 

 described resembles Chcetoderma, but in several important characters it 

 differs. The body is short ; the radula is very large, of the distichous 

 type, with 28 transverse rows ; dorsal salivary glands are present ; stomach 

 and liver are well-developed and distinct from the relatively long slender 

 intestine. 



* Bull. Soc. Zool. France, xxix. (1905) pp. 221-9. 



t Zool. Jahrb. Suppl., Heft vi., Fauna Chilensis (1904) pp. 353-406 (4 pis. and 

 2 figs.). 



t MT. Zool. Stat. Neapel, xvi. (1904) pp. 458-68 (1 pi. and 5 figs.). 

 § Zool. Anzeig., sxviii. (1904) pp. 329-31. 



