146 SUMMARY OF CURRENT RESEARCHES RELATING TO 



containing novel results, it is worthy of special notice as a simple and 

 comprehensive account of Tunicate anatomy. 



New Tunicates from the Clyde.* — Dr. James Rankin makes a pre- 

 liminary report on the Tunicata of Millport and neighbourhood. His 

 list includes Fritillaria gracilis sp. n., Glossophorum variabile sp. n., and 

 Psammaplidium molle sp. n. 



Mollusca. 



o. Cephalopoda. 



Experiments on "Eggs of Squid.f — Wl. Schimkewitsch, in an ap- 

 pendix to his recent paper on the eggs of Loligo, amplifies his previous 

 statements as to intra vitam coloration with metbylen-blue. He finds 

 that tbe staining of the cells is not due to the staining of chromatin 

 granules, but to the presence in the cells of what appear to be coloured 

 particles of yolk, which have apparently undergone a process of meta- 

 morphosis under the influence of the nucleus. Ordinary yolk stains only 

 feebly, but these particles become intensely blue. They are present in 

 the cells of the embryo until almost the last stages of development, 

 persisting longest in certain special regions, e.g. in the ventral epithe- 

 lium. They are most abundant in cells which are about to give rise to 

 the rudiment of an organ, and therefore afford a means of tracing the 

 first origin of the different organs. Their presence in such cells is to 

 be correlated with the increased metabolism of the cells. 



y. Gastropoda. 



Phylacites of Hyalina.| — Emile Andre under this name describes 

 certain structures, apparently of defensive nature, which occur in the 

 skin of the species of this genus, and present certain analogies to 

 nematocysts. When still inclosed in the parent-cell (phylacoblast), a 

 phylacite is a rounded transparent body inclosing a vesicle within 

 which lie 3-20 refracting spherules. After expulsion it appears some- 

 what mushroom-shaped, and is inverted so that the vesicle bearing the 

 spherules at its tip is protruded at the surface. Tho phylacoblasts are 

 at first similar to ordinary connective-tissue cells ; but when the phylacite 

 is completely developed, they have lost both nucleus and protoplasm. 

 From the staining reactions it is clear that the phylacites are not com- 

 posed of mucus, but their chemical composition, no less than their exact 

 function, remains obscure. 



5. Lamellibranchiata. 



Structure of Cardium edule.§ — J. Johnstone publishes a compre- 

 hensive and fully illustrated account of the structure and habits of the 

 edible cockle, with special reference to its occurrence in Lancashire. 



Eyes of Mollusca.|| — Dr. Richard Hesse has made a series of obser- 

 vations on the eyes of certain Lamellibranchs (Area, Lima, Pecten), on 



* Communications Millport Station, i. (1900) pp. 42-53. 



t Zeitschr. wiss. Zool., lxviii. (1900) pp. 478-9. Cf. this Journal, 1900, p. 33. 

 t Rev. Suisse Zool., viii. (1900) pp. 425-33 (1 pi.). 



§ Trans. Liverpool Biol. Soo., xiv. (1900) pp. 178-261 (6 pis.). Also published 

 as Memoir II. of Liverpojl Marine Biology Committee. 



|| Zeitschr. wiss. Zool., lxviii. (1900) pp. 379-477 (8 pis. and 1 fig.). 



